102 lines
1.6 KiB
C
102 lines
1.6 KiB
C
#include <x86.h>
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#include <user/stdio.h>
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#include <user/syscall.h>
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#define PRINTFBUF_SIZE 4096
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struct printfbuf {
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u32 lock;
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char buf[PRINTFBUF_SIZE];
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char *buf_p;
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int cnt;
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};
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static struct printfbuf printfb = {
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.buf_p = printfb.buf
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};
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static void
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printfputch(int ch, struct printfbuf *b)
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{
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b->cnt++;
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*b->buf_p++ = (char)ch;
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if (b->buf_p == b->buf + PRINTFBUF_SIZE) {
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write(STDOUT, b->buf, sizeof(b->buf));
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b->buf_p = b->buf;
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}
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}
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int
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vprintf(const char *fmt, va_list ap)
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{
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struct printfbuf *b = &printfb;
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// 上个自旋锁，保证线程安全（不建议用中断）计组课上讲过，相信大家的记忆力
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while (xchg(&b->lock, 1) == 1);
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b->cnt = 0;
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vprintfmt((void *)printfputch, b, fmt, ap);
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int rc = b->cnt;
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xchg(&b->lock, 0);
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return rc;
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}
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int
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printf(const char *fmt, ...)
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{
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va_list ap;
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int rc;
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va_start(ap, fmt);
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rc = vprintf(fmt, ap);
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va_end(ap);
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return rc;
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}
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/*
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* 将printf的缓冲区全写出去
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*/
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void
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fflush()
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{
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struct printfbuf *b = &printfb;
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write(STDOUT, b->buf, b->buf_p - b->buf);
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b->buf_p = b->buf;
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}
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#define GETCHBUG_SIZE 1024
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struct getchbuf {
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u32 lock;
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u8 buf[GETCHBUG_SIZE];
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u8 *st, *en;
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};
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static struct getchbuf getchb = {
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.st = getchb.buf,
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.en = getchb.buf,
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};
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u8
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getch()
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{
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struct getchbuf *b = &getchb;
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// 上个自旋锁，保证线程安全（不建议用中断）计组课上讲过，相信大家的记忆力
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while (xchg(&b->lock, 1) == 1);
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if (b->st == b->en) {
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b->st = b->en = b->buf;
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b->en += read(STDIN, b->buf, sizeof(b->buf));
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}
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u8 rc = b->st == b->en ? -1 : *b->st++;
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xchg(&b->lock, 0);
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return rc;
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} |