diff --git a/assets/Computer_Organization_and_Design_1681729306797_0.edn b/assets/Computer_Organization_and_Design_1681729306797_0.edn index 75fd1f8..69573a8 100644 --- a/assets/Computer_Organization_and_Design_1681729306797_0.edn +++ b/assets/Computer_Organization_and_Design_1681729306797_0.edn @@ -4533,4 +4533,4 @@ :page 334}, :content {:text " Nonetheless,"}, :properties {:color "green"}}], - :extra {:page 336}} + :extra {:page 335}} diff --git a/assets/HTMFS_Strong_Consistency_Comes_for_Free_with_1682646967100_0.edn b/assets/HTMFS_Strong_Consistency_Comes_for_Free_with_1682646967100_0.edn new file mode 100644 index 0000000..d89c87b --- /dev/null +++ b/assets/HTMFS_Strong_Consistency_Comes_for_Free_with_1682646967100_0.edn @@ -0,0 +1 @@ +{:highlights [], :extra {:page 2}} diff --git a/assets/HTMFS_Strong_Consistency_Comes_for_Free_with_1682646967100_0.pdf b/assets/HTMFS_Strong_Consistency_Comes_for_Free_with_1682646967100_0.pdf new file mode 100644 index 0000000..a0c8a6c Binary files /dev/null and b/assets/HTMFS_Strong_Consistency_Comes_for_Free_with_1682646967100_0.pdf differ diff --git a/assets/HTMFS_Strong_Consistency_Comes_for_Free_with_1682647018871_0.edn b/assets/HTMFS_Strong_Consistency_Comes_for_Free_with_1682647018871_0.edn new file mode 100644 index 0000000..1708a95 --- /dev/null +++ b/assets/HTMFS_Strong_Consistency_Comes_for_Free_with_1682647018871_0.edn @@ -0,0 +1,35 @@ +{:highlights [{:id #uuid "644b27f5-e3e1-4a24-a507-820e0abbbfd5", + :page 2, + :position {:bounding {:x1 182.17857360839844, + :y1 300.017879486084, + :x2 235.5746307373047, + :y2 319.44643783569336, + :width 734.4, + :height 950.4}, + :rects ({:x1 182.17857360839844, + :y1 300.017879486084, + :x2 235.5746307373047, + :y2 319.44643783569336, + :width 734.4, + :height 950.4}), + :page 2}, + :content {:text "Abstract"}, + :properties {:color "yellow"}} + {:id #uuid "644b2866-2f98-49f4-a914-2d1400d47e3b", + :page 2, + :position {:bounding {:x1 115.08929443359375, + :y1 800.5804138183594, + :x2 218.93569946289062, + :y2 825.7232666015625, + :width 979.1999999999999, + :height 1267.1999999999998}, + :rects ({:x1 115.08929443359375, + :y1 800.5804138183594, + :x2 218.93569946289062, + :y2 825.7232666015625, + :width 979.1999999999999, + :height 1267.1999999999998}), + :page 2}, + :content {:text "Introduction"}, + :properties {:color "yellow"}}], + :extra {:page 2}} diff --git a/assets/HTMFS_Strong_Consistency_Comes_for_Free_with_1682647018871_0.pdf b/assets/HTMFS_Strong_Consistency_Comes_for_Free_with_1682647018871_0.pdf new file mode 100644 index 0000000..a0c8a6c Binary files /dev/null and b/assets/HTMFS_Strong_Consistency_Comes_for_Free_with_1682647018871_0.pdf differ diff --git a/assets/XPC_Architectural_Support_for_Secure_and_Efficient_Cross_1682647057931_0.edn b/assets/XPC_Architectural_Support_for_Secure_and_Efficient_Cross_1682647057931_0.edn new file mode 100644 index 0000000..d7933e0 --- /dev/null +++ b/assets/XPC_Architectural_Support_for_Secure_and_Efficient_Cross_1682647057931_0.edn @@ -0,0 +1,18 @@ +{:highlights [{:id #uuid "644b281a-d7fa-4163-8e75-a39d74215bfa", + :page 1, + :position {:bounding {:x1 55.37500324845314, + :y1 188.41964721679688, + :x2 115.27688923478127, + :y2 203.27679443359375, + :width 629.9999999999999, + :height 815.2941176470588}, + :rects ({:x1 55.37500324845314, + :y1 188.41964721679688, + :x2 115.27688923478127, + :y2 203.27679443359375, + :width 629.9999999999999, + :height 815.2941176470588}), + :page 1}, + :content {:text "ABSTRACT"}, + :properties {:color "yellow"}}], + :extra {:page 1}} diff --git a/assets/XPC_Architectural_Support_for_Secure_and_Efficient_Cross_1682647057931_0.pdf b/assets/XPC_Architectural_Support_for_Secure_and_Efficient_Cross_1682647057931_0.pdf new file mode 100644 index 0000000..a8fd382 Binary files /dev/null and b/assets/XPC_Architectural_Support_for_Secure_and_Efficient_Cross_1682647057931_0.pdf differ diff --git a/logseq/bak/logseq/config/2023-04-16T10_45_09.261Z.Desktop.edn b/logseq/bak/logseq/config/2023-04-28T00_43_20.080Z.Desktop.edn similarity index 99% rename from logseq/bak/logseq/config/2023-04-16T10_45_09.261Z.Desktop.edn rename to logseq/bak/logseq/config/2023-04-28T00_43_20.080Z.Desktop.edn index 657d2d7..c3910f3 100644 --- a/logseq/bak/logseq/config/2023-04-16T10_45_09.261Z.Desktop.edn +++ b/logseq/bak/logseq/config/2023-04-28T00_43_20.080Z.Desktop.edn @@ -344,6 +344,7 @@ :file/name-format :triple-lowbar :ui/show-brackets? true :feature/enable-timetracking? false + :journal/page-title-format "EEE, yyyy/MM/dd" ;; specify the format of the filename for journal files ;; :journal/file-name-format "yyyy_MM_dd" diff --git a/logseq/bak/pages/hls__Computer_Organization_and_Design_1681729306797_0/2023-04-28T00_43_20.095Z.Desktop.md b/logseq/bak/pages/hls__Computer_Organization_and_Design_1681729306797_0/2023-04-28T00_43_20.095Z.Desktop.md new file mode 100644 index 0000000..8c1c974 --- /dev/null +++ b/logseq/bak/pages/hls__Computer_Organization_and_Design_1681729306797_0/2023-04-28T00_43_20.095Z.Desktop.md @@ -0,0 +1,1189 @@ +file:: [Computer_Organization_and_Design_1681729306797_0.pdf](../../../../assets/Computer_Organization_and_Design_1681729306797_0.pdf) +file-path:: ../../../../assets/Computer_Organization_and_Design_1681729306797_0.pdf + +- # Computer Abstractions and Technology + ls-type:: annotation + hl-page:: 25 + hl-color:: yellow + id:: 643d2848-6edf-4c05-92c7-4a7de1b9cd22 +- Classes of Computing Applications and Their Characteristics + ls-type:: annotation + hl-page:: 28 + hl-color:: yellow + id:: 643e2b9c-0bc2-4b02-b2b1-33e25539d5b9 +- Below Your Program + ls-type:: annotation + hl-page:: 36 + hl-color:: yellow + id:: 643ea1cf-af0e-45ba-97b3-376fd21ee1e3 + collapsed:: true + - From a High-Level Language to the Language of Hardware + ls-type:: annotation + hl-page:: 37 + hl-color:: yellow + id:: 643ea1d7-cd7d-4e81-8d6f-c268aab04f68 +- Under the Covers + ls-type:: annotation + hl-page:: 39 + hl-color:: yellow + id:: 643ea295-e170-403a-a43d-71777bb41d9b + collapsed:: true + - The five classic components of a computer are input, output, memory, datapath, and control + ls-type:: annotation + hl-page:: 40 + hl-color:: yellow + id:: 643ea2f7-1fa7-4c12-ad2d-34a90d6968b7 + - liquid crystal displays (LCDs) + hl-page:: 41 + ls-type:: annotation + id:: 643ea91c-7643-4563-9341-f85096313a3b + hl-color:: yellow + - The LCD is not the source of light but instead controls the transmission of light. There is a background light source and the LCD has many rods which bend light to make it pass through. When applied with a current, the rod no more bends light thus controlling the pixel. + - an active matrix that has a tiny transistor switch at each pixel to precisely control current and make sharper images + ls-type:: annotation + hl-page:: 41 + hl-color:: yellow + id:: 643ead73-e1a6-4f10-82c5-2760a4ce839f + - instruction set architecture + hl-page:: 45 + ls-type:: annotation + id:: 643eb029-9fe9-4013-a4a2-1365e195333b + hl-color:: yellow + - interface between the hardware and low-level software, distinguish architecture from implementation +- Technologies for Building Processors and Memory + ls-type:: annotation + hl-page:: 47 + hl-color:: yellow + id:: 643eb311-6b10-4fa3-9aa3-dfd5a59acf2c + collapsed:: true + - Semiconductor, silicon: add materials to silicon that allow tiny areas to transform into one of three devices: Excellent conductor, Excellent insulator and Transistor (conduct/insulate at some conditions) + hl-page:: 48 + ls-type:: annotation + id:: 643eb66d-0294-46ab-a182-20021b2495c5 + hl-color:: yellow + - Silicon ingot sliced into Blank wafers, processed into Patterned wafers, and then Tested wafer, diced into Tested dies, bonded to package, finally Tested packaged dies + - die: Rectangular sections cut from a wafer (actually chip) + - yield: Percentage of good dies from the total dies on the wafer +- Performance + ls-type:: annotation + hl-page:: 51 + hl-color:: yellow + id:: 643ec3be-027e-48b5-90e0-cd4a5e901691 + collapsed:: true + - response/execution time: time between the start and completion of a task + hl-page:: 52 + ls-type:: annotation + id:: 643fb234-d566-4913-a03b-c574e6a623c4 + hl-color:: yellow + - $\text{Performance}_X = \frac{1}{\text{Execution time}_X}$ + - Relative Performance: A is ==n times as fast as== B, which means the same program runs for 1/n time on A of that on B + hl-page:: 54 + ls-type:: annotation + id:: 643fe045-80bb-4c47-b601-3fdc9175581d + hl-color:: yellow + - throughput: the total amount of work done in a given time + hl-page:: 53 + ls-type:: annotation + id:: 643fb242-9401-42fa-bddc-d93e571b6e99 + hl-color:: yellow + - Measuring Performance + ls-type:: annotation + hl-page:: 55 + hl-color:: yellow + id:: 6440d1fd-a2c1-4d4c-a493-3b5c7d91448e + - Elapsed time: total time to complete a task, including RAM access, IO and other overhead. + - CPU time: time that CPU spends on computing for this task and not includes IO or waiting for schedule + - user CPU time + - system CPU time: time that OS performing tasks on behalf of the program (syscall?) + - CPU Performance and Its Factors + ls-type:: annotation + hl-page:: 56 + hl-color:: yellow + id:: 6440d4c6-9dc2-4712-9d25-6386325581e5 + - clock cycles: discrete time intervals + - clock period: length of a clock cycle + - clock rate: inverse of the clock period + - For a specific program, CPU time = CPU clock cycles $\times$ Clock cycle time = CPU clock cycles $\div$ Clock rate + - Instruction Performance + ls-type:: annotation + hl-page:: 58 + hl-color:: yellow + id:: 6440d70f-cde0-41ca-af1b-82d5a777a7a8 + - CPU clock cycles = Instruction count $\times$ CPI + - CPI (clock Cycles Per Instruction): average number of cycles each instruction takes to execute (for one program) + - compare two different implementations of the same ISA + - The Classic CPU Performance Equation + ls-type:: annotation + hl-page:: 59 + hl-color:: yellow + id:: 6440d99c-e080-4352-8c2d-7d35e897a2ee + - CPU time = Instruction count $\times$ CPI $\div$ Clock rate + - The formulas separates 3 key factors affecting the performance + - The only complete and reliable measure of computer performance is time. + hl-page:: 61 + ls-type:: annotation + id:: 6440dc59-a80f-4185-9692-8e4122cad4b4 + hl-color:: yellow + - CPI depends on a wide variety of design details in the computer + hl-page:: 61 + ls-type:: annotation + id:: 6440dcd2-ae75-4a59-a2c5-aff6e3bf7953 + hl-color:: yellow +- The Power Wall + ls-type:: annotation + hl-page:: 63 + hl-color:: yellow + id:: 6440df39-4ac7-4efc-b59a-64db6354ca0f + collapsed:: true + - dynamic energy: The energy consumed when transistors switch states, primary source of energy consumption for CMOS. + - The energy of a single transition: $\text{Energy} \propto \frac12 \times \text{Capacitive load} \times \text{Voltage}^2$ + - The power required per transistor: $\text{Power} \propto \frac12 \times \text{Capacitive load} \times \text{Voltage}^2 \times \text{Frequency switched}$ + - Frequency switched is a function of the *clock rate* + - Capacitive load is a function of *fanout* (number of transistors connected to an output) and the technology (capacitance of wires and transistors). + - Main way to reduce power is to lower the *voltage*. + - There is problem with low voltage: this makes the capacitor leakage increase. (static energy) +- The Sea Change: The Switch from Uniprocessors to Multiprocessors + ls-type:: annotation + hl-page:: 66 + hl-color:: yellow + id:: 6440e9ca-16a4-48ed-9648-adafb74ce097 + collapsed:: true + - This section is about the difficulty of parallel programming and relative materials. +- Fallacies and Pitfalls + ls-type:: annotation + hl-page:: 72 + hl-color:: yellow + id:: 6440ea56-fdd5-426f-9a76-d5b5a7465c55 + collapsed:: true + - Amdahl's Law: $\text{Execution time after improvement} = \frac{\text{Execution time affected by improvement} }{\text{Amount of improvement}} + \text{Execution time unaffected}$ + hl-page:: 72 + ls-type:: annotation + id:: 6441179d-ae59-49b4-8903-874cb5b7c9cd + hl-color:: yellow + - Thus, we CANNOT expect ==improvement of one aspect== of a computer to ==increase overall performance by an amount proportional== to the size of improvement. + - Computers at low utilization don't necessarily use little power, or in other words, power consumption is not proportional to the system's load. + hl-page:: 73 + ls-type:: annotation + id:: 6441212c-596a-463c-a47a-04478b16268b + hl-color:: yellow + - MIPS (million instructions per second) = $\frac{\text{Instruction count}}{\text{Execution time} \times 10^6} = \frac{\text{Clock rate}}{\text{CPI} \times 10^6}$ + hl-page:: 74 + ls-type:: annotation + id:: 64412369-dd7a-4a26-9979-be7179f38df6 + hl-color:: yellow + - Problem 1: it doesn't take into account the *Instruction count*, or the capability of each instruction. We should not compare computers with different ISAs. + - Problem 2: MIPS varies between programs even on the same computer. + - Problem 3: MIPS can vary independently from performance. +- Word List 1 + collapsed:: true + - omnipresent 无所不在的 ubiquitous + hl-page:: 27 + ls-type:: annotation + id:: 643e2b82-f5a5-411e-9571-d494858c175a + hl-color:: green + - credo 信条,教义 + ls-type:: annotation + hl-page:: 30 + hl-color:: green + id:: 643e473a-2f03-419b-ad3a-8309c33dff15 + - unraveling 解开;阐明; + hl-page:: 31 + ls-type:: annotation + id:: 643e47b3-cc6c-4fd1-83a9-0510b16a5e9c + hl-color:: green + - acronyms 首字母缩略词 + ls-type:: annotation + hl-page:: 32 + hl-color:: green + id:: 643e485f-8de8-41bf-86ac-812ba202f4c8 + - leverage 影响力;杠杆作用 + hl-page:: 33 + ls-type:: annotation + id:: 643e4871-3ebb-4578-9227-b40a534adeac + hl-color:: green + - intrinsic 固有的, 内在的, 本质的 + ls-type:: annotation + hl-page:: 33 + hl-color:: green + id:: 643e4882-a5ea-4bff-9b5f-17f585313142 + - weave 编织;杜撰 + hl-page:: 34 + ls-type:: annotation + id:: 643e492d-5e63-4b9b-93f7-4f44bf50158e + hl-color:: green + - rod 杆;竿;棒 + ls-type:: annotation + hl-page:: 41 + hl-color:: green + id:: 643ea931-ff7e-4bd7-96d1-b7eab4dcc563 + - helix n. 螺旋 + hl-page:: 41 + ls-type:: annotation + id:: 643ea93a-fa50-486a-b74a-d96f2a4df9aa + hl-color:: green + - raster 光栅 + ls-type:: annotation + hl-page:: 41 + hl-color:: green + id:: 643ea8f8-7e5f-42e3-a04a-01cd91f25d13 + - brawn 体力;发达的肌肉 + ls-type:: annotation + hl-page:: 42 + hl-color:: green + id:: 643eaede-f413-4717-9136-e28363909bb3 + - quadruple 四倍的;四重的; + hl-page:: 48 + ls-type:: annotation + id:: 643eb37e-2927-4100-b8b3-c76bbe5450f4 + hl-color:: green + - slam 砰地关上(门或窗);抨击 + hl-page:: 65 + ls-type:: annotation + id:: 6440e306-7625-4883-b3f0-fbdca42d92e3 + hl-color:: green + - faucet 水龙头 + ls-type:: annotation + hl-page:: 65 + hl-color:: green + id:: 6440e5e4-e02f-43e3-9311-64f8b6d67f75 + - unwieldy + ls-type:: annotation + hl-page:: 65 + hl-color:: green + id:: 6440e73c-8061-47b2-bc37-522db24f1707 + - startling + ls-type:: annotation + hl-page:: 66 + hl-color:: green + id:: 6440e8c9-0024-4751-8233-43e8cea16699 + - stiffer + ls-type:: annotation + hl-page:: 68 + hl-color:: green + id:: 6440e99d-0c7d-4acb-9ba7-9172e1d383d8 + - ensnared + ls-type:: annotation + hl-page:: 72 + hl-color:: green + id:: 6440ec21-aef2-4494-8b50-d16a83c0d9bb + - corollary + ls-type:: annotation + hl-page:: 72 + hl-color:: green + id:: 6441170f-b51b-453a-b612-0b71b2b6032d + - demoralize + ls-type:: annotation + hl-page:: 72 + hl-color:: green + id:: 64411718-be78-469d-9b83-0dfd9c83338b + - plague + ls-type:: annotation + hl-page:: 72 + hl-color:: green + id:: 64411720-4c6a-49ce-8a72-4aa19e7b8482 + - preclude + ls-type:: annotation + hl-page:: 75 + hl-color:: green + id:: 6440ebb6-a98d-465f-8345-3da49486f653 + - constituent + ls-type:: annotation + hl-page:: 75 + hl-color:: green + id:: 6440ebc6-59b1-4b7e-ae67-75559989873b + - impeachable + ls-type:: annotation + hl-page:: 75 + hl-color:: green + id:: 6440ebd7-8c0c-4a18-9d86-bd95714f58ac +- # Instructions: Language of the Computer + ls-type:: annotation + hl-page:: 83 + hl-color:: yellow + id:: 64412821-6b54-47a0-9317-a4b042989fdf +- Operations of the Computer Hardware + ls-type:: annotation + hl-page:: 86 + hl-color:: yellow + id:: 64412ca1-c9b5-4d6b-ba19-d353992dd2f1 + collapsed:: true + - Three-operand arithmetic instructions +- Operands of the Computer Hardware + ls-type:: annotation + hl-page:: 89 + hl-color:: yellow + id:: 64412cc0-59a8-4a38-9094-1a7bd916a41f + collapsed:: true + - Registers, where operands of arithmetic instructions must reside + - Register size is a *word* (32 bit) + - 32 registers in MIPS. + - fewer registers to keep clock cycles fast (though 31 regs may not be faster then 32 regs) + - instruction format (5-bit field for register number) + - data transfer instructions + ls-type:: annotation + hl-page:: 91 + hl-color:: yellow + id:: 64412fc0-7ad1-4c8a-9c03-c198e741605b + - memory to register or inverse + - alignment restriction: *word*s must start at addresses that are multiples of 4. As a result, there is some restrictions on the address for `lw/sw` + hl-page:: 92 + ls-type:: annotation + id:: 6441425c-134d-449d-ae39-4db48a67054c + hl-color:: yellow + - memory is addressed by byte, remember this especially when dealing with array indices because the type of array elements decides the offset. + - MIPS is in the big-endian camp (though the textbook says so, the latest MIPS32 by default is little endian) + hl-page:: 93 + ls-type:: annotation + id:: 64414940-7d06-4339-af0b-974b1b34dbc5 + hl-color:: yellow + - Constant or Immediate Operands + ls-type:: annotation + hl-page:: 95 + hl-color:: yellow + id:: 64414a51-2d38-48ff-b0c0-bc53f9c5fadb + - Constant operands occur frequently, and by ==including constants inside arithmetic instructions==, operations are much ==faster== and use ==less energy== than if constants were ==loaded from memory==. + hl-page:: 95 + ls-type:: annotation + id:: 64414af2-05ea-4a88-baf6-a19462b4c3a9 + hl-color:: yellow + - Since MIPS supports ==negative constants==, there is no need for subtract immediate in MIPS. + ls-type:: annotation + hl-page:: 96 + hl-color:: yellow + id:: 64414b4e-cf31-4e7f-8320-2f1bbcbf9b32 +- Signed and Unsigned Numbers + ls-type:: annotation + hl-page:: 96 + hl-color:: yellow + id:: 64414b5f-de73-4bbc-812d-8ebd0f082ea0 + collapsed:: true + - binary digits + hl-page:: 96 + ls-type:: annotation + id:: 64414bb1-c764-493b-b555-4e241a31f255 + hl-color:: yellow + - value of `i`th digit: $d \times \text{Base}^i$ + - LSB and MSB + - Numbers have infinite number of digits, binary bit patterns are simply representatives of numbers. Thus, there are various ways of handling *overflow*. + hl-page:: 97 + ls-type:: annotation + id:: 64414c34-4dc9-4127-9938-faf0374b6c29 + hl-color:: yellow + - Signed numbers + - **sign and magnitude**: add a separate sign bit. Problems with this approach, need an extra step to set the sign during calculation, negative and positive zero + hl-page:: 98 + ls-type:: annotation + id:: 64414d4d-71a4-44df-9475-d710bfee40d3 + hl-color:: yellow + - **two's compliment** + - the value of this form can be written as $(d_{31} \cdot -2^{31}) + d_{30} \cdot 2^{30} + \dots$, note the first $-2^{31}$ + id:: 64414f1b-142c-4301-a5a2-6dc0ad3b102b + - **one's compliment**: negate operation is to simply invert each bit + - sign extension: copy the sign repeatedly to fill the rest of the register when loading from memory + hl-page:: 99 + ls-type:: annotation + id:: 64414fbb-4773-4332-bf21-f533847d0bde + hl-color:: yellow + - This trick works because positive 2's complement numbers really have an infinite number of 0s on the left and negative 2's complement numbers have an infinite number of 1s. The binary bit pattern representing a number hides leading bits to fit the width of the hardware; sign extension simply restores some of them. + hl-page:: 101 + ls-type:: annotation + id:: 64415085-a9e5-4193-a5d1-9c90f5d63ea8 + hl-color:: yellow +- Representing Instructions in the Computer + ls-type:: annotation + hl-page:: 103 + hl-color:: yellow + id:: 64414d2f-3ea8-45a6-9a7a-b84f74a554cf + collapsed:: true + - MIPS Fields + ls-type:: annotation + hl-page:: 105 + hl-color:: yellow + id:: 64415179-3df0-431e-9e53-8608796931dd + - In order to keep the instructions regular (aligned by word), MIPS has irregular layouts for different types of instruct. + - R-type: `op | rs | rt | rd | shamt | funct` + - I-type: `op | rs | rt | constant/address` + - The 16-bit address means a `lw` can only load from a region of $\pm 2^{15}$ bytes of the base register. + - here `rt` serves as the destination register +- Logical Operations + ls-type:: annotation + hl-page:: 110 + hl-color:: yellow + id:: 64415118-595d-4125-b641-333d82a58006 + collapsed:: true + - `sll` and `srl`, use the `shamt` (shift amount) field + - `andi` `ori` extend their 16-bit constant field by filling 0s + - there is no exact instruction for bitwise not, but a `nor` (not or, `a NOR b = NOT(a OR b)`) instruction (perhaps in order to keep the 3-operand format) +- Instructions for Making Decisions + ls-type:: annotation + hl-page:: 113 + hl-color:: yellow + id:: 644154b4-a07e-46fd-aa88-178297b61434 + collapsed:: true + - conditional branches: `bne` and `beq` + hl-page:: 113 + ls-type:: annotation + id:: 644156a7-b2b5-4010-97e3-a432f077cd33 + hl-color:: yellow + - Loops + ls-type:: annotation + hl-page:: 115 + hl-color:: yellow + id:: 64415778-92af-4d30-b3b4-0b3dddd397f4 + - `slt` and `slti`: if `rs < rt`/`rs < imm` then `rd=1` else `rd=0` + - MIPS assemblers use the combination `slt/slti` and `beq/bne` and `$zero` to create all relative conditions + - `sltu/stliu` signed and unsigned comparison are different, thus an unsigned version is provided + - Case/Switch Statement: *jump address table* and `jr` instruction (the runtime destination address is stored in register) + hl-page:: 118 + ls-type:: annotation + id:: 644159a7-3b96-4924-8260-0cb300307c86 + hl-color:: yellow +- Supporting Procedures in Computer Hardware + ls-type:: annotation + hl-page:: 119 + hl-color:: yellow + id:: 644156f5-e485-4140-be11-6ef87a585383 + collapsed:: true + - `jal` jumps to an address and simultaneously saves the address of the following instruction in `$ra` + - `jr` jumps to the address specified in a register + - Calling convention for register: + - `$a0-$a3`: four argument registers in which to pass parameters + - `$v0–$v1`: two value registers in which to return values + - `$ra`: one return address register to return to the point of origin + - `$t0–$t9`: temporary registers that are not preserved by the *callee* on a procedure call + id:: 644163d9-8d4b-43e8-acec-57a835c4ce48 + - `$s0–$s7`: saved registers that must be preserved on a procedure call (if used, *callee* saves and restores them) + - `$sp`: stack pointer to the most recently allocated address, `push` substract from `$sp` and `pop` add to `$sp` + - `$fp`: frame pointer to the first word of the frame of a procedure + - `$gp`: pointer to global static data + - FIGURE 2.11 What is and what is not preserved across a procedure call. + ls-type:: annotation + hl-page:: 125 + hl-color:: yellow + id:: 64416615-2966-4adb-a524-845337e588d3 + - Allocating Space for New Data on the Stack + ls-type:: annotation + hl-page:: 126 + hl-color:: yellow + id:: 6441667f-2639-458b-91fd-8bf6b5a2c6ae + - stack is also used to store variables that are local to the procedure but do not fit in registers + - procedure frame or activation record + ls-type:: annotation + hl-page:: 126 + hl-color:: yellow + id:: 64416688-3f6e-444e-b265-3e4a36ec51b8 + - a frame pointer offers a stable base register within a procedure for local memory-references, in that stack pointer changes during the procedure +- ASCII and String + hl-page:: 129 + ls-type:: annotation + id:: 644167c0-1ac2-42df-b01d-4fff03a393e7 + hl-color:: yellow + collapsed:: true + - `lb/lbu` and `sb` load/store the right most byte, `lh/lhu` and `sh` load/store the lower half word + - Some notes about how to organize a string + - character size + - length or end mark +- MIPS Addressing for 32-bit Immediates and Addresses + ls-type:: annotation + hl-page:: 134 + hl-color:: yellow + id:: 6441f1a7-4442-466f-9edc-776f6e0e6ecb + collapsed:: true + - 32-Bit Immediate Operands: `lui` loads a half word to the upper 16 bits of a register, and then a `ori` sets the lower 16 bits, thus loading a 32-bit immediate + hl-page:: 135 + ls-type:: annotation + id:: 6441fb16-91e4-42d8-94bf-5718dd9fc91b + hl-color:: yellow + - Addressing in Branches and Jumps + ls-type:: annotation + hl-page:: 136 + hl-color:: yellow + id:: 64427722-3a05-43f1-b00e-7dcc30cc74ff + - J-type instruction: `op | address (26 bits)` + - Since MIPS instructions are all 4-byte aligned, the unit of the address in PC-relative addressing is actually *word*. For example, 16-bit address in branch instruction actually represents an 18-bit address. + - MIPS Addressing Mode + ls-type:: annotation + hl-page:: 139 + hl-color:: yellow + id:: 64427a40-988f-4430-aaa5-84d3926c6234 + - 1. Immediate addressing: the operand is a constant within the instruction itself (e.g., `addi $rd, $rs, 4`) + 2. Register addressing: the operand is a register (e.g., `add $rd, $rs, $rt`) + 3. Base (displacement) addressing: the operand is at the memory location whose address is the sum of a register and a constant in the instruction (e.g., `lw $rd, 4($rs)`) + 4. PC-relative addressing: the branch address is the sum of the PC and a constant in the instruction (e.g., `beq $rs, $rt, #addr`) + 5. Pseudo-direct addressing: the jump address is the 26 bits of the instruction concatenated with the upper bits of the PC (e.g., `j #addr`) +- Parallelism and Instructions: Synchronization + ls-type:: annotation + hl-page:: 144 + hl-color:: yellow + id:: 644284b0-dd95-46e5-829f-4509200e5f8d + collapsed:: true + - a set of hardware primitives with the ability to atomically read and modify a memory location + hl-page:: 144 + ls-type:: annotation + id:: 64428547-07fb-49e2-9e3f-a7ac95b7e8e0 + hl-color:: yellow + - **atomic exchange**: interchange a value in a register for a value in memory + - Introduces some challenges in the processor design + - `while (xchg(&lock, 1) == 1) ;` + - **MIPS `ll/sc`**: a pair of instructions in which the second instruction returns a value showing whether the pair of instructions as if one atomic instruction. + - `while (ll(&lock) == 1 && sc(&lock, 1)) ;` + - `sc` will fail after either another attempted store to the `ll`ed address or ==any exception==. It is possible to create deadlock where `sc` can never complete due to repeated page faults. +- Translating and Starting a Program + ls-type:: annotation + hl-page:: 146 + hl-color:: yellow + id:: 64428b6e-1dba-4bd4-ab91-d18ae9cb9cf6 + collapsed:: true + - Assembler + ls-type:: annotation + hl-page:: 147 + hl-color:: yellow + id:: 64428b72-2291-4380-a2ad-dc5cdc82315e + - pseudoinstructions: assembler translates these instructions into equivalent machine instructions. Register `$at` is reserved for such translations. + hl-page:: 147 + ls-type:: annotation + id:: 64428b7b-0678-4fc3-a105-71fdc6185144 + hl-color:: yellow + - Example 1: `move $t0, $t1` -> `add $t0, $t1, $zero` + - Example 2: `blt $t0, $t1, LABEL1` -> `slt $at, $t0, $t1; bne $at, $zero, LABEL1` + - The assembler turns the assembly language program into an *object file*, which is a combination of ==machine language instructions==, ==data==, and information needed to place instructions properly in memory (==symbol table==, ==relocation information==). + hl-page:: 148 + ls-type:: annotation + id:: 64428ce2-cd44-4d6d-a311-dc7aa3f656ab + hl-color:: yellow + - The object file for UNIX systems typically contains six distinct pieces: *object file header*, *text segment*, *static data segment*, *relocation information*, *symbol table*, and *debug information* + hl-page:: 148 + ls-type:: annotation + id:: 64428f56-bd42-4cc4-a4dd-bf8b05e76fc3 + hl-color:: yellow + - Linker + ls-type:: annotation + hl-page:: 149 + hl-color:: yellow + id:: 64428f9a-632e-4bdb-80d5-56febc2bb977 + - Re-compile the whole program at each change to a single procedure is huge waste, so compile/assemble independently and finally link them together. + - 3 steps for the linker: + - hl-page:: 149 + ls-type:: annotation + id:: 6442909f-b0b5-4706-8454-f89466e3ff7e + hl-color:: yellow + 1. Place code and data modules symbolically in memory. + 2. Determine the addresses of data and instruction ==labels==. + 3. Patch both the internal and external ==references==. + - Example Problem: Linking Object Files + hl-page:: 150 + ls-type:: annotation + id:: 6442957a-fb16-4069-8e74-d470c01ba18c + hl-color:: yellow + - Dynamically Linked Libraries + ls-type:: annotation + hl-page:: 152 + hl-color:: yellow + id:: 644292fb-c10c-43f6-8152-941b009e14c2 + - Library routines are not linked and loaded until the program is run. Keep extra info on the location and name of non-local procedures. + hl-page:: 152 + ls-type:: annotation + id:: 644295c2-95e3-4da8-ba89-5470c9049fce + hl-color:: yellow + - The *program loader* uses the extra information to find the proper libraries and ==update all external references==. + - Lazy procedure linkage: Instead of linking all library routines that might be called, link only those are actually called at runtime. + - Assume there is a table of entries for external routines, at static linkage stage, set them all to a dummy address of a dynamic linker/loader. At runtime, the program jumps to this dummy address, and executes this linker/loader which finds the desired routine, remaps it and changes the address in the indirect jump location. Next time this routine is called, this indirect jump will go to the desired routine. +- A C Sort Example to Put It All Together + ls-type:: annotation + hl-page:: 155 + hl-color:: yellow + id:: 6442a0c7-e518-46f3-979d-9c104093343b + collapsed:: true + - Skipped, since it is easy +- Arrays versus Pointers + ls-type:: annotation + hl-page:: 164 + hl-color:: yellow + id:: 6442a0b8-5961-423d-bbcf-96cf55fd55cf + collapsed:: true + - An example piece of code which iterate over an array by both pointer and index + - Skipped, since it is easy +- Advanced Material: Compiling C and Interpreting Java + ls-type:: annotation + hl-page:: 168 + hl-color:: yellow + id:: 6442a09e-3edb-4593-833a-626506177900 + collapsed:: true + - Skipped, since it is compiler's job (Control Flow Graph???) +- Real Stuff: ARMv7 (32-bit) Instructions + ls-type:: annotation + hl-page:: 194 + hl-color:: yellow + id:: 6442a15d-dfe5-49b0-9b78-5f109e674e2f +- Real Stuff: x86 Instructions + ls-type:: annotation + hl-page:: 198 + hl-color:: yellow + id:: 6442a152-baff-4ccb-aee2-2f548e14903e +- Real Stuff: ARMv8 (64-bit) Instructions + ls-type:: annotation + hl-page:: 207 + hl-color:: yellow + id:: 6442a1ad-0491-48d7-84b7-7feba159d9dd + collapsed:: true + - The philosophy of ARMv8 is much closer to MIPS than ARMv7. For example, the `$zero`, the `beq/bne` instead of the condition bit +- Design Principles + collapsed:: true + - Design Principle 1: Simplicity favors regularity. + ls-type:: annotation + hl-page:: 88 + hl-color:: yellow + id:: 644152b5-ee31-4da9-86e4-33d7472f04c3 + - Design Principle 2: Smaller is faster. + ls-type:: annotation + hl-page:: 90 + hl-color:: yellow + id:: 644152aa-00c2-4542-abaf-7048e6d37904 + - Design Principle 3: Good design demands good compromises. + ls-type:: annotation + hl-page:: 106 + hl-color:: yellow + id:: 64415292-0727-4366-8717-ecca11267baf +- Word List 2 + collapsed:: true + - palatable 可口的;味美的 + ls-type:: annotation + hl-page:: 86 + hl-color:: green + id:: 64412a38-84ed-4f97-b83d-911772eb7158 + - rationale 基本原理;根本原因 reason + hl-page:: 86 + ls-type:: annotation + id:: 64412bbd-513c-4e00-8576-7ef88749e552 + hl-color:: green + - moot 无考虑意义的 + ls-type:: annotation + hl-page:: 99 + hl-color:: green + id:: 64414e6e-e6f7-4d05-865f-a18455c509ba + - dichotomy 二分法;两面性;(the separation between two opposite groups) + hl-page:: 117 + ls-type:: annotation + id:: 6441591a-02ed-4556-8fd7-5fdb310063e7 + hl-color:: green + - spill (使)洒出,泼出,溢出: + ls-type:: annotation + hl-page:: 121 + hl-color:: green + id:: 64416330-597c-4245-8d53-a5dc643ea05f + - wax and wane 月亮盈/亏 + hl-page:: 127 + ls-type:: annotation + id:: 64416671-9318-4296-9588-c0421c02cdd2 + hl-color:: green + - interpose 将…置于(二者)之间;插话 + hl-page:: 144 + ls-type:: annotation + id:: 64428502-8d37-4bad-a24f-6edfa9796740 + hl-color:: green + - succinct 简明的;言简意赅的 concise + hl-page:: 148 + ls-type:: annotation + id:: 64428c72-5e4f-4f33-a1ac-cadd4610f04a + hl-color:: green + - stitch 缝 + ls-type:: annotation + hl-page:: 149 + hl-color:: green + id:: 6442903b-ae86-4608-8d83-60771782b088 + - anatomy 解剖学 + ls-type:: annotation + hl-page:: 168 + hl-color:: green + id:: 64429b75-4433-4e39-8085-ad2e791dbf33 + - headstart 领先 + ls-type:: annotation + hl-page:: 207 + hl-color:: green + id:: 6442a2ee-8c2e-4ed2-a67f-23db50972a71 + - toil (长时间)苦干,辛勤劳作 + hl-page:: 209 + ls-type:: annotation + id:: 6442a05d-69ba-4161-9ffa-bb305a17fcf1 + hl-color:: green +- # Arithmetic for Computers + hl-page:: 225 + ls-type:: annotation + id:: 6442a5d0-e073-4cd4-a6c6-1bb664ee952a + hl-color:: yellow +- Addition and Subtraction + ls-type:: annotation + hl-page:: 227 + hl-color:: yellow + id:: 64433f1c-c023-429e-88d0-46cad778477c + collapsed:: true + - Addition is to add digits bit by bit from right to left with carries passed to the left digit. + - Subtraction uses addition, negate the second operand before adding. + - Overflow + collapsed:: true + - The result cannot be represented with the hardware. + - ==No overflow== can occur when ==adding operands with different signs== or ==subtracting operands with the same sign==. + - Overflow occurs when adding 2 positives and the sum is negative, or vice versa; and when subtracting a negative from a positive and get a negative, or vice versa. + - For a software detection, you can use `xor` to detect sign difference. + - For overflow (carry) of unsigned numbers, though often ignored, use the inequation $(\text{MAXUINT})2^{32}-1 \lt A + B \rightarrow 2^{32}-1 -A \lt B \rightarrow \overline{A} \lt B$ + - 这里补充一下408的内容,说了3种判断方法(不过本质上一样的),设 $A + B = S$ + - 一位符号位,就是英文教材里面的方法,适合软件判断 (因为你没有进位信号也没有双符号位)$\text{OF} = A_sB_s\overline{S_s}+\overline{A_s}\overline{B_s}S_s$ + - 两位符号位,无非就是给MSB前面添2位罢了。计算结果的双符号位 $S_{s1}S_{s2}$ 有4种组合,分别表示无溢出和正负溢出,判断为 $\text{OF} = S_{s1}\oplus S_{s2}$ + - 符号位进位和最高位进位,$\text{OF} = C_{n} \oplus C_{n-1}$ + - In MIPS, `add/addi/sub` causes exceptions on overflow; while `addu/addiu/subu` does not cause exceptions on overflow. + - Since C ignores overflow, it always uses `*u` instructions. + - saturating operation: When overflow, set the result to the MAX/MIN value rather than a modulo to 2^32 + hl-page:: 230 + ls-type:: annotation + id:: 644347f7-9833-4208-99f7-655f94b5a7b5 + hl-color:: yellow +- Multiplication + ls-type:: annotation + hl-page:: 232 + hl-color:: yellow + id:: 64434f2d-d63b-4840-96da-918f7a04cb97 + collapsed:: true + - Names of the operands: `product = multiplicand * multiplier` + - Observation + - n-bit *multiplicand* and m-bit *multiplier* result in a (m+n)-bit *product* (overflow) + - The manual multiplication method in essence is a ==shift-and-add== process. + - Sequential Version of the Multiplication Algorithm and Hardware + ls-type:: annotation + hl-page:: 233 + hl-color:: yellow + id:: 64435253-b5bf-4832-ad91-025cede3bafd + collapsed:: true + - Naive version + - Three registers, namely 64-bit multiplicand, 32-bit multiplier and 64-bit product. + - ![image.png](../assets/image_1682135277029_0.png){:height 223, :width 449} + - Pseudo code for the algorithm + ```C + uint64_t multiplicand = A; + uint32_t multiplier = B; + uint64_t product = 0; + for (int i = 0; i < 32; ++ i) { + if (multiplier & 0x1) product += multiplicand; // 1. test multiplier[0] and add to product + // else do nothing, or add 0 + multiplicand <<= 1; // left shift multiplicand + multiplier >>= 1; // right shift multiplier + } + ``` + - Though the textbook says that each iteration takes 3 clock cycles, I think all these can be done in 1 cycle (虽然时序会比较垃圾就是了). The following refined version no doubt needs only 1 cycle each iteration. + - Refined version + - one 64-bit register for product which right-shifts once at a tick + - 31 cycles (the first partial product is already in product register by initialization, so save one addition from the original 32 iterations) + - ![image.png](../assets/image_1682136092546_0.png) + - Signed Multiplication + ls-type:: annotation + hl-page:: 236 + hl-color:: yellow + id:: 64435d8f-d70f-4968-be40-ddbf8ef5a19e + - The easiest solution is that, first convert all operands to positive and calculate the sign separately; after multiplication, convert the the product to its correct sign. + - The *refined version* is ready to deal with signed multiplication by the following 2 steps: + - Enable sign extension on right shift of *product* register. + - Subtract rather than add on the last partial product. This operation originates from ((64414f1b-142c-4301-a5a2-6dc0ad3b102b)) + - Then we can get a 32-bit product in the lower word of the *product* register. + - Faster Multiplication + ls-type:: annotation + hl-page:: 236 + hl-color:: yellow + id:: 6443dd4d-c534-4911-9e81-3b4b0ef396d9 + - A balance between resource and speed + - FIGURE 3.7 Fast multiplication hardware. + hl-page:: 237 + ls-type:: annotation + id:: 6443e016-d955-4433-9956-46ad682890ae + hl-color:: yellow + collapsed:: true + - ![image.png](../assets/image_1682170089022_0.png) + - Only $\log_2(32) = 5$ times addition. + - Unroll the loop into a tree-like + - There are many other ways to implement a multiplier circuit, such as Array Multiplier using Carry-Save Addition, or pipeline it, or booth. + - Principle of booth algorithm + - The simplest Radix-2 booth multiplier is based on such an observation (again): + $$ + A = A_{\text{n-1}}A_{\text{n-2}}\dots A_{\text{1}}A_{\text{0}} + \\ = - A_{n-1} \times 2^{n-1} + \sum_{i=0}^{n-2} A_{i}\times 2^{i} + \\ = - A_{n-1} \times 2^{n-1} + (2 - 1)\sum_{i=0}^{n-2} A_{i}\times 2^{i} + \\= (A_{n-2}- A_{n-1})\cdot 2^{n-1} + (A_{n-3}- A_{n-2})\cdot2^{n-2} \cdots (A_{1}- A_{0})\cdot2^{1} + (A_{-1}- A_{0})\cdot 2^{0} + $$ + - When $A_{i-1} = A_{i}$, the result is 0. Thus, Radix-2 Booth Algorithm examines the 2 LSBs and decides which operation to perform (shift (`00/11`) or add (`01`) or subtract (`10`)). + - Extending to Radix-4, the item looks like this: $(A_{2k+1}-2A_{2k}+A_{2k-1})\times 2^{2k}$. And we will have a more complicated operation table since the algorithm examines 3 bits. + - Radix-4 Booth Algorithm halves the number of partial products, thus improving the performance. +- Division + ls-type:: annotation + hl-page:: 238 + hl-color:: yellow + id:: 6443e24f-a691-45aa-809c-2e01aca20e0b + collapsed:: true + - $\text{dividend} = \text{quotient} \times \text{divisor} + \text{remainder}, \text{divisor} \gt \text{remainder}$ + collapsed:: true + - As for signed division, watch out for the *remainder*. There may be more than one seemingly reasonable pair of (*quotient*, *remainder*). One general rule for this is that, *remainder* has the same sign as the *dividend*. + - A Division Algorithm and Hardware (Unsigned) + hl-page:: 238 + ls-type:: annotation + id:: 6443e2eb-9d81-471b-9033-0e325140b4f2 + hl-color:: yellow + - Naive version + - ![image.png](../assets/image_1682171249934_0.png) + - Pseudo code + ```C + void div(uint32_t A, uint32_t B) { + uint64_t Divisor = B << 32; + uint64_t Remainder = A; + uint32_t Quotient = 0; + for (int i = 0; i < 33; ++ i) { + Remainder = Remainder - Divisor; // 1. try subtract + if (Remainder >= 0) { + Quotient = (Quotient | 1) << 1; // 2.a. suffice + } + else { + Quotient = (Quotient | 0) << 1; // 2.b. cannot subtract, restore + Remainder = Remainder + Divisor; + } + Divisor = Divisor >> 1; // 3. next bit + } + } + ``` + - Refined version + collapsed:: true + - ![image.png](../assets/image_1682173423614_0.png) + - Use less resource, only a 64-bit register is needed, which is `0 | Dividend` at initialization and `Remainder | Quotient` after 32 cycles (32 left shifts). + - A working SystemVerilog implement + ```verilog + module divider( + input logic clk, + input logic rst, + input logic en, + input logic [31:0] operandA, + input logic [31:0] operandB, + output logic operation_valid, + output logic busy, + output logic [63:0] result + ); // unsigned divider + parameter COUNT = 6'd32; + logic [5:0] count; + logic [31:0] divisor; + logic [31:0] alu_result; + logic restore; + logic [63:0] remainder; + always @(posedge clk, negedge rst) + if (!rst) divisor <= 32'b0; + else if (en && count == 0) divisor <= operandB; + always @(posedge clk, negedge rst) + if (!rst) remainder <= 64'b0; + else if (en && count == 0) remainder <= {32'b0, operandA}; + else if (busy) begin + if (restore) remainder <= remainder << 1; + else remainder <= {alu_result[30:0], remainder[31:0], 1'b1}; + end + always @(posedge clk, negedge rst) + if (!rst || !en) count <= 0; + else if (count == 0) count <= 1; + else if (count < COUNT) count <= count + 1; + else count <= 0; + assign operation_valid = (operandB == 32'b0 && en) ? 1'b0 : 1'b1; + assign busy = en && count; + assign alu_result = remainder[63:32] - divisor; + assign restore = remainder[63:32] < divisor; + assign result = {alu_result[31:0], remainder[30:0], ~restore}; + // due to implementation issues, the remainder part will be over-shifted in the end + // here is a workaround + endmodule + ``` + - 无符号除法也可以用加减交替法(Non-restoring Division),一种简单的改进。国内的计组教材上讲的都是定点小数,如果需要做整数的话,需要把 Divisor 先左移 N 位。好像说,不恢复余数法,其实是 SRT 方法的一种特殊情况来着。感觉还是没怎么搞明白,这东西可以单独开一门课,不过无所谓了,反正题会做就行。 + - 我的评价是,看这个吧。COMPUTER ARITHMETIC : Algorithms and Hardware Designs + - 补码除法(爱来自408) + - 加减交替法:符号位和数值位一起参加运算(全部是补码),商符自然形成。 + - 先做一次加减法运算:若 Dividend 和 Divisor 同号,则相减;否则相加。 + - 然后重复N次:若 Remainder 和 Divisor 同号,商上1,左移 Remainder 并减 Divisor;否则 Quotient 上0,左移 Remainder 并加 Divisor + - 最后一步给 Quotient 恒置1 + - 不过说实在的,我没理解,手动算好像也不对劲,==不知道哪里出了问题==,过天再看看。这东西的设计还挺好玩的。 + - Faster Division + ls-type:: annotation + hl-page:: 243 + hl-color:: yellow + id:: 6444043e-8c74-474e-a4f0-b2011ebb9b10 + - Similar to multiplier, there are also many ways to build a divider. However, unlike multiplier, divider cannot use array-adder, since it cannot be known ahead whether the subtraction is available. There is a method based on lookup table and prediction, called *SRT division*. +- Floating Point + ls-type:: annotation + hl-page:: 245 + hl-color:: yellow + id:: 644410ff-f158-431d-ab11-22f32e63a6da + collapsed:: true + - Normalized number: a number in scientific notation without leading 0s. + - binary point: the point, but in base 2 + hl-page:: 245 + ls-type:: annotation + id:: 644494f0-4e7e-4356-bf49-5d7f61999a78 + hl-color:: yellow + - floating point normalized form: $1.xxxxxxxx_{\text{two}} \times 2^{yyyy}$. Since there is no leading 0s, the only bit to the left of the *binary point* is 1. + - Floating-Point Representation + ls-type:: annotation + hl-page:: 246 + hl-color:: yellow + id:: 644495bf-6828-4439-a332-f5a9a176adaf + - A single-precision floating point has 32 bits, `1 | 8 | 23` bit(s) for the 3 components `s | exponent | fraction` + - A double-precision floating point has 64 bits, `1 | 11 | 52` bits for the 3 components. + - General form of floating-point numbers: $(-1)^{\text{s}} \times \text{F} \times 2^{\text{E}}$ + - overflow: the exponent is too large + hl-page:: 247 + ls-type:: annotation + id:: 6444979f-bc17-4cf6-9a68-0a7098db96b6 + hl-color:: yellow + - underflow: the ==negative== exponent is too large + hl-page:: 247 + ls-type:: annotation + id:: 644497a1-f169-4386-8e44-cf46566f6d47 + hl-color:: yellow + - **significant**: the 24-bit or 53-bit number comprised of the implicit leading 1 and the *fraction*. + - IEEE 754 encoding of floating-point numbers. + hl-page:: 248 + ls-type:: annotation + id:: 6444991d-e3c9-4161-863e-2c65db02a575 + hl-color:: yellow + - **Represent 0**: Since 0 has no leading 1, a reserved *exponent* `0` is there to represent the number. + - **Represent Infinity/NaN**:Two unusual cases are given another reserved *exponent* `255/2047`, representing *infinity* (`fraction = 0`) and *NaN* (`fraction != 0`) + - **Biased notation**: To simplify the sorting of floating-point numbers, the *exponent* field is designed to be an unsigned integer. But we also have to represent negative exponents, thus the *exponent* field is biased by `127/1023`. In other words, the real value of the exponent is the *exponent* field subtract bias. + - The real value of an IEEE-754 floating-point (==normalized==) number could be expressed as: $(-1)^{\text{s}}\times (1+\text{Fraction})\times 2^{\text{Exponent-Bias}}$ + - Ranges from $\pm 1.00\dots00_{\text{two}}\times 2^{-126}$ to $\pm 1.11\dots11_{\text{two}}\times 2^{+127}$ + - **de-normalized numbers**: The *exponent* field is `0`, but the actual exponent is `-126/-1022`. And there is no implicit leading 1. This form can represent a number smallest down to $0.00\dots01_{\text{two}} \times 2^{-126} = 1.0_{\text{two}}\times 2^{-149}$ + hl-page:: 271 + ls-type:: annotation + id:: 6444a660-b04c-4dd5-9f03-1df86f5feaf2 + hl-color:: yellow + collapsed:: true + - However, this prevents FPUs from getting faster, some architects raise exceptions for de-normalized IEEE-754 (they just don't implement such support) + - Floating-Point Addition + ls-type:: annotation + hl-page:: 252 + hl-color:: yellow + id:: 64449f20-2e2b-4aba-a152-fb5013cee9df + - FIGURE 3.14 Floating-point addition. + ls-type:: annotation + hl-page:: 254 + hl-color:: yellow + id:: 6444a190-55ce-4d72-b776-f65bd79c402e + - (1) Compare the exponents of the 2 numbers. Shift the smaller number to the right until its exponent would match the larger one + - (2) Add the significands + - (3) Normalize the sum, either `rsh` and `exp++` or `lsh` and `exp--` + - Check overflow/underflow + - (4) Round the significand + - Check if the result is normalized, in case rounding adds to the MSB. If not, go to (3). + - FIGURE 3.15 Block diagram of an arithmetic unit dedicated to floating-point addition. + ls-type:: annotation + hl-page:: 256 + hl-color:: yellow + id:: 6444a33a-1be3-46cf-88d7-bda594ff889b + - Floating-Point Multiplication + ls-type:: annotation + hl-page:: 255 + hl-color:: yellow + id:: 6444a351-91c2-4d55-b74d-e9b3bf0b1f3f + - FIGURE 3.16 Floating-point multiplication. + ls-type:: annotation + hl-page:: 258 + hl-color:: yellow + id:: 6444a815-7f89-4638-9bc0-a2539cf80a27 + - (1) Add the biased *exponents* of the 2 numbers (and subtract one bias since it is added twice) to get the new *exponent* field + - (2) Multiply the significands + - Different from addition, ==exponent alignment is no needed==. Directly multiply the significands. + - (3) Normalize and check over/underflow + - (4) Round the significand to the appropriate number of bits, and check normalized (or go to (3)) + - (5) Set the sign of the product + - Floating-Point Instructions in MIPS + ls-type:: annotation + hl-page:: 260 + hl-color:: yellow + id:: 6444a4ea-ad13-4a57-a881-cb7cbae7f65f + - Special instructions: arithmetic(single/double) `add.s/d`, comparison `c.eq.s/d`, branch `bclt/bclf`, data transfer `lwc1/swc1` + - Floating-point registers: `$f0` to `$f31`, each 32-bit. A double-precision register is actually an even-odd pair of single-precision registers (e.g., double register `$f2` = `{$f2, $f3}`) + - Accurate Arithmetic + ls-type:: annotation + hl-page:: 267 + hl-color:: yellow + id:: 6444ac21-f605-497c-b86e-4d36484f6e3a + - Keep 2 extra bit on the right during ==intermediate additions==, since hardware cannot hold infinite bits for intermediates. They are *guard* and *round*. + - **sticky bit**: a third bit which indicates whether there are any non-zero bits to the right of the *round bit* + - units in the last place (ulp): The number of bits in error in the LSBs (right-most bits) of the significand between the actual number and the rounded number. ==Measure of accuracy==. + hl-page:: 268 + ls-type:: annotation + id:: 6444af4d-4e28-41ab-97b9-a4442cbe9d9a + hl-color:: yellow + - IEEE 754 has 4 rounding modes: always round up (toward $+\infin$), always round down(toward $-\infin$), truncate, and round to nearest even. + hl-page:: 268 + ls-type:: annotation + id:: 6444b015-6430-4fce-b780-988a0caa63f5 + hl-color:: yellow +- Parallelism and Computer Arithmetic: Subword Parallelism + ls-type:: annotation + hl-page:: 271 + hl-color:: yellow + id:: 6444bd6c-1170-4f97-932b-af66246ff486 + collapsed:: true + - Many multimedia applications use 8-bit or 16-bit data units, thus the processor can perform simultaneous operations on short vectors of these smaller operands (which are stored in a single word-size register) + - subword parallelism, data level parallelism, SIMD +- Real Stuff: Streaming SIMD Extensions and Advanced Vector Extensions in x86 + ls-type:: annotation + hl-page:: 273 + hl-color:: yellow + id:: 6444bda7-e1ae-495b-86eb-5507878df5d8 + collapsed:: true + - multiple floating-point operands packed into a single 128-bit SSE2 register + hl-page:: 273 + ls-type:: annotation + id:: 6444bfc1-7314-4629-ae26-defc51e37a96 + hl-color:: yellow + - load and store multiple operands per instruction, perform arithmetic operations on multiple operands +- Going Faster: Subword Parallelism and Matrix Multiply + ls-type:: annotation + hl-page:: 274 + hl-color:: yellow + id:: 6444bdac-2bc0-490a-ac86-88c702b83c65 + collapsed:: true + - DGEMM: Double precision GEneral Matrix Multiply. A commonly used program for demonstration. + hl-page:: 274 + ls-type:: annotation + id:: 6444c0b0-7629-423c-b600-03286f22c6bd + hl-color:: yellow + - An interesting example for how to use SIMD to speedup matrix multiply. + ```C + void dgemm(int n, double* A, double* B, double* C) { + for (int i = 0; i < n; ++i) + for (int j = 0; j < n; ++j) { + double cij = C[i+j*n]; /* cij = C[i][j] */ + for( int k = 0; k < n; k++ ) + cij += A[i+k*n] * B[k+j*n]; /* cij += A[i][k]*B[k][j] */ + C[i+j*n] = cij; /* C[i][j] = cij */ + } + } + + void dgemm_AVX(int n, double* A, double* B, double* C) { + for (int i = 0; i < n; i+=4) + for (int j = 0; j < n; j++) { + __m256d c0 = _mm256_load_pd(C+i+j*n); /* c0 = C[i][j] */ + for(int k = 0; k < n; k++) + c0 = _mm256_add_pd(c0, _mm256_mul_pd(_mm256_load_pd(A+i+k*n), _mm256_broadcast_sd(B+k+j*n))); + /* c0 += A[i][k]*B[k][j] */ + _mm256_store_pd(C+i+j*n, c0); /* C[i][j] = c0 */ + } + } + ``` +- Fallacies and Pitfalls + ls-type:: annotation + hl-page:: 278 + hl-color:: yellow + id:: 6444bdb2-6eb9-44b2-afcf-0a844265f162 + collapsed:: true + - Pitfall: ==Floating-point addition is not associative==. + ls-type:: annotation + hl-page:: 278 + hl-color:: yellow + id:: 6444c121-8df1-44b0-8077-5258bb7e907d + - Parallel execution strategies that work for integer data types ==NOT always work for floating-point== data types. + hl-page:: 279 + ls-type:: annotation + id:: 6444c1f0-95bb-4cb4-b82c-b68e52f8b53b + hl-color:: yellow + - Pitfall: The MIPS instruction add immediate unsigned (addiu) ==sign-extends== its 16-bit immediate field. + ls-type:: annotation + hl-page:: 279 + hl-color:: yellow + id:: 6444c1c5-55d6-4ee4-a522-7775b374d047 +- Word List 3 + - quirk + ls-type:: annotation + hl-page:: 227 + hl-color:: green + id:: 64433ef2-0591-499f-b056-b2664d81156e + - vexing + ls-type:: annotation + hl-page:: 232 + hl-color:: green + id:: 64434f3c-f512-4f58-a6f2-05e7aa355ec6 + - vague + ls-type:: annotation + hl-page:: 267 + hl-color:: green + id:: 6444aca4-859a-4303-b126-5b4fb95801ea + - equitable + ls-type:: annotation + hl-page:: 268 + hl-color:: green + id:: 6444ae4a-b788-41ca-bf5a-f3e65eae3f37 + - quandary + ls-type:: annotation + hl-page:: 279 + hl-color:: green + id:: 6444c22c-5633-40b1-9a04-dc9ac66b5cbd + - glitch + ls-type:: annotation + hl-page:: 281 + hl-color:: green + id:: 6444c19b-acea-4882-994b-06a1c34e86fb +- # The Processor + ls-type:: annotation + hl-page:: 291 + hl-color:: yellow + id:: 6444be95-7530-4e08-bdf8-c05ea9cc5b9d +- Introduction + ls-type:: annotation + hl-page:: 293 + hl-color:: yellow + id:: 6444e82b-27ec-4755-9dd9-e1d543ab66d3 + collapsed:: true + - A Basic MIPS Implementation + ls-type:: annotation + hl-page:: 293 + hl-color:: yellow + id:: 6444e833-44e0-4dd0-82f9-cdcdac95dc04 + - A subset of MIPS ISA: Memory-reference (`lw` `sw`), Arithmetic (`add` `sub` `and` `or` `slt`), and Branch (`beq` `j`) + - Several common steps: + - 1. Send the PC to memory and fetch the instruction + - 2. Read 1 or 2 registers, using the fields of the instruction + - 3. Except `j`, all instruction classed use the ALU after reading the registers, though for different purposes (arithmetic, address calculation, comparison) + - 4. After ALU, the actions required to complete various classes of instructions differ, such as load/store memory, write to register or change PC. + - FIGURE Abstract view of the MIPS subset's implementation + hl-page:: 295 + ls-type:: annotation + id:: 64477e93-0b18-4efa-83c0-2c8e71b90457 + hl-color:: yellow + - FIGURE Basic implementation with multiplexors/control. + hl-page:: 296 + ls-type:: annotation + id:: 64477f1f-1cb6-4a55-bfad-148b4a3fb467 + hl-color:: yellow + - **Multiplexor**: One destination may have multiple sources, and thus we need to select from these sources according to the type of the instruction. + - **Control unit**: accepts the instruction as input, and generates signals to control other functional units (e.g., ALU, Memory) and the multiplexors. +- Logic Design Conventions + ls-type:: annotation + hl-page:: 297 + hl-color:: yellow + id:: 64477d00-f17e-40fd-8178-6e21175025a0 + - Combinational elements and State elements + - For combinational, outputs depend only on the current inputs + hl-page:: 297 + ls-type:: annotation + id:: 6447833a-b83a-40a0-98fa-59b6fa78c15c + hl-color:: yellow + - State elements completely characterize the computer, which has (at least) 2 inputs and 1 output. The clock is used to determine when to write, and a state element can be read at any time. + hl-page:: 297 + ls-type:: annotation + id:: 644a2196-f210-49e3-bf47-5439713057aa + hl-color:: yellow + - Clocking Methodology + hl-page:: 298 + ls-type:: annotation + id:: 644a2259-9a11-4a2d-bbb8-bc71ef75b9ab + hl-color:: yellow + - Edge-triggered clocking: state elements are only updated on a clock edge. + - Combinational logic must have its inputs come from a set of state elements and its outputs written into a set of state elements. These inputs are values written in a previous cycle, while the outputs are values that can be used in a following clock cycle. + hl-page:: 298 + ls-type:: annotation + id:: 644a24c1-45e7-4763-8284-25b7d875d2b6 + hl-color:: yellow +- Building a Datapath + ls-type:: annotation + hl-page:: 300 + hl-color:: yellow + id:: 644a22b7-e481-4b81-b97d-717955fa09f6 \ No newline at end of file diff --git a/pages/IPADS 面试.md b/pages/IPADS 面试.md index 744c8b4..ce3af2a 100644 --- a/pages/IPADS 面试.md +++ b/pages/IPADS 面试.md @@ -12,4 +12,6 @@ - Zero-Change Object Transmission for Distributed Big Data Analytics  ATC'22 - Microsecond-scale Preemption for Concurrent GPU-accelerated DNN Inferences  OSDI'22 - No Provisioned Concurrency: Fast RDMA-codesigned Remote Fork for Serverless Computing OSDI'23 - - Harmonizing Performance and Isolation in Microkernels with Efficient Intra-kernel Isolation and Communication  ATC'20 \ No newline at end of file + - Harmonizing Performance and Isolation in Microkernels with Efficient Intra-kernel Isolation and Communication  ATC'20 +- ![HTMFS Strong Consistency Comes for Free with.pdf](../assets/HTMFS_Strong_Consistency_Comes_for_Free_with_1682647018871_0.pdf) +- ![XPC Architectural Support for Secure and Efficient Cross.pdf](../assets/XPC_Architectural_Support_for_Secure_and_Efficient_Cross_1682647057931_0.pdf) \ No newline at end of file diff --git a/pages/hls__Computer_Organization_and_Design_1681729306797_0.md b/pages/hls__Computer_Organization_and_Design_1681729306797_0.md index 50cf032..cc1fe32 100644 --- a/pages/hls__Computer_Organization_and_Design_1681729306797_0.md +++ b/pages/hls__Computer_Organization_and_Design_1681729306797_0.md @@ -1423,7 +1423,9 @@ file-path:: ../../../../assets/Computer_Organization_and_Design_1681729306797_0. hl-page:: 335 hl-color:: yellow id:: 644a8636-5eb3-45d2-ab01-a0acd29747b0 + - Five stages: IF, ID, EX, MEM, WB - Word List 4 + collapsed:: true - anatomy 解剖学 ls-type:: annotation hl-page:: 321 diff --git a/pages/hls__HTMFS_Strong_Consistency_Comes_for_Free_with_1682647018871_0.md b/pages/hls__HTMFS_Strong_Consistency_Comes_for_Free_with_1682647018871_0.md new file mode 100644 index 0000000..d979402 --- /dev/null +++ b/pages/hls__HTMFS_Strong_Consistency_Comes_for_Free_with_1682647018871_0.md @@ -0,0 +1,16 @@ +file:: [HTMFS_Strong_Consistency_Comes_for_Free_with_1682647018871_0.pdf](../assets/HTMFS_Strong_Consistency_Comes_for_Free_with_1682647018871_0.pdf) +file-path:: ../assets/HTMFS_Strong_Consistency_Comes_for_Free_with_1682647018871_0.pdf + +- Abstract + ls-type:: annotation + hl-page:: 2 + hl-color:: yellow + id:: 644b27f5-e3e1-4a24-a507-820e0abbbfd5 +- Introduction + ls-type:: annotation + hl-page:: 2 + hl-color:: yellow + id:: 644b2866-2f98-49f4-a914-2d1400d47e3b + - Earlier FSs optimize for performance, but provide loose consistency guarantees + - With the speedup of modern storage devices, strong consistency can ease the pain of software programming. + - Strong consistency implies per-request sequential consistency. \ No newline at end of file diff --git a/pages/hls__XPC_Architectural_Support_for_Secure_and_Efficient_Cross_1682647057931_0.md b/pages/hls__XPC_Architectural_Support_for_Secure_and_Efficient_Cross_1682647057931_0.md new file mode 100644 index 0000000..9222d2f --- /dev/null +++ b/pages/hls__XPC_Architectural_Support_for_Secure_and_Efficient_Cross_1682647057931_0.md @@ -0,0 +1,8 @@ +file:: [XPC_Architectural_Support_for_Secure_and_Efficient_Cross_1682647057931_0.pdf](../assets/XPC_Architectural_Support_for_Secure_and_Efficient_Cross_1682647057931_0.pdf) +file-path:: ../assets/XPC_Architectural_Support_for_Secure_and_Efficient_Cross_1682647057931_0.pdf + +- ABSTRACT + ls-type:: annotation + hl-page:: 1 + hl-color:: yellow + id:: 644b281a-d7fa-4163-8e75-a39d74215bfa \ No newline at end of file