BSD 2 development

[unix-history] / misc / getc.s

/ getw/getc -- get words/characters from input file
/ fopen -- open a file for use by get(c|w)

indir = 0

.globl  _getc, _getw, _fopen
.globl  cerror
.comm   _errno,2

_fopen:
       mov     r5,-(sp)
       mov     sp,r5
       mov     4(r5),0f
       sys     0; 9f
       .data
9:      sys     open; 0:..; 0
       .text
       bes     badret
       mov     6(r5),r1
       mov     r0,(r1)+
       clr     (r1)+
       clr     r0
       mov     (sp)+,r5
       rts     pc

_getw:
       clr     _errno
       mov     r5,-(sp)
       mov     sp,r5
       mov     4(r5),r1
       sub     $2,2(r1)
       bge     1f
       cmp     2(r1),$-1
       blt     2f
       movb    *4(r1),-(sp)
       jsr     pc,fill
       mov     4(r1),r0
       br      3f
2:
       jsr     pc,fill
       dec     2(r1)
1:
       mov     4(r1),r0
       movb    (r0)+,-(sp)
3:
       movb    (r0)+,1(sp)
       mov     r0,4(r1)
       mov     (sp)+,r0
       mov     (sp)+,r5
       rts     pc

_getc:
       mov     r5,-(sp)
       mov     sp,r5
       mov     4(r5),r1
       dec     2(r1)
       bge     1f
       jsr     pc,fill
1:
       clr     r0
       bisb    *4(r1),r0
       inc     4(r1)
       mov     (sp)+,r5
       rts     pc

fill:
       mov     r1,r0
       add     $6,r0
       mov     r0,0f
       mov     r0,4(r1)
       mov     (r1),r0
       sys     0; 9f
.data
9:      sys     read; 0:..; 512.
.text
       bes     badret
       dec     r0
       bmi     badret
       mov     r0,2(r1)
       rts     pc

badret:
       jmp     cerror