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cc65/libsrc/atari/rwcommon.s

44 lines
1010 B
ArmAsm

;
; common iocb setup routine for read, write
; expects __fastcall__ parameters (int fd, void *buf, int count)
;
.include "atari.inc"
.include "errno.inc"
.import popax
.import fdtoiocb
.export __rwsetup
__rwsetup:
pha ; push size in stack
txa
pha
jsr popax ; get buffer address
pha
txa
pha
jsr popax ; get handle
jsr fdtoiocb ; convert to iocb
bmi iocberr ; negative (X=$FF or A>$7F) on error.
tax
pla ; store address
sta ICBAH,x
pla
sta ICBAL,x
pla ; store length
sta ICBLH,x
pla
sta ICBLL,x
ora ICBLH,x ; returns Z if length is 0
rts
iocberr:pla
pla
pla
pla
ldx #$FF ; indicate error + clear ZF
rts