1
0
mirror of https://github.com/cc65/cc65.git synced 2024-11-18 00:07:21 +00:00
cc65/libsrc/cbm/rwcommon.s
2020-12-27 17:54:49 -05:00

45 lines
1.1 KiB
ArmAsm

;
; Ullrich von Bassewitz, 17.11.2002
;
; Common stuff for the read/write routines
;
.export rwcommon
.import popax, popptr1
.importzp ptr1, ptr2, ptr3, tmp2
.include "errno.inc"
.include "filedes.inc"
;--------------------------------------------------------------------------
; rwcommon: Pop the parameters from stack, preprocess them and place them
; into zero page locations. Return carry set if the handle is invalid,
; return carry clear if it is ok. If the carry is clear, the handle is
; returned in A.
.proc rwcommon
inx
stx ptr2+1
tax
inx
stx ptr2 ; Save count with each byte incremented separately
jsr popptr1 ; Get buf to ptr1, Y=0 by call
sty ptr3
sty ptr3+1 ; Clear ptr3
jsr popax ; Get the handle
cpx #$01
bcs @L9
cmp #MAX_FDS ; Set carry if fd too large
sta tmp2
@L9: rts ; Return with result in carry
.endproc