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[unix-history] / sys / dmr / gput.s

/ Character list get/put

ps      = 0177776
spl     = 230

.globl  _getc
.globl  _putc

.globl  _cfreelist

_getc:
       mov     2(sp),r1
       mov     ps,-(sp)
       spl     5
       mov     2(r1),r2        / first ptr
       beq     9f              / empty
       movb    (r2)+,r0        / character
       bic     $!377,r0
       mov     r2,2(r1)
       dec     (r1)+           / count
       bne     1f
       clr     (r1)+
       clr     (r1)+           / last block
       br      2f
1:
       bit     $7,r2
       bne     3f
       mov     -10(r2),(r1)    / next block
       add     $2,(r1)
2:
       dec     r2
       bic     $7,r2
       mov     _cfreelist,(r2)
       mov     r2,_cfreelist
3:
       mov     (sp)+,ps
       rts     pc
9:
       clr     4(r1)
       mov     $-1,r0
       mov     (sp)+,ps
       rts     pc

_putc:
       mov     2(sp),r0
       mov     4(sp),r1
       mov     ps,-(sp)
       mov     r2,-(sp)
       mov     r3,-(sp)
       spl     5
       mov     4(r1),r2        / last ptr
       bne     1f
       mov     _cfreelist,r2
       beq     9f
       mov     (r2),_cfreelist
       clr     (r2)+
       mov     r2,2(r1)        / first ptr
       br      2f
1:
       bit     $7,r2
       bne     2f
       mov     _cfreelist,r3
       beq     9f
       mov     (r3),_cfreelist
       mov     r3,-10(r2)
       mov     r3,r2
       clr     (r2)+
2:
       movb    r0,(r2)+
       mov     r2,4(r1)
       inc     (r1)            / count
       clr     r0
       mov     (sp)+,r3
       mov     (sp)+,r2
       mov     (sp)+,ps
       rts     pc
9:
       mov     pc,r0
       mov     (sp)+,r3
       mov     (sp)+,r2
       mov     (sp)+,ps
       rts     pc