read.s

来自「unix v7是最后一个广泛发布的研究型UNIX版本」· S 代码 · 共 25 行

/ C library -- read

/ nread = read(file, buffer, count);
/ nread ==0 means eof; nread == -1 means error

.globl	_read
.globl	cerror
.read = 3.

_read:
	mov	r5,-(sp)
	mov	sp,r5
	mov	4(r5),r0
	mov	6(r5),0f
	mov	8(r5),0f+2
	sys	0; 9f
	bec	1f
	jmp	cerror
1:
	mov	(sp)+,r5
	rts	pc
.data
9:
	sys	.read; 0:..; ..