mirror of https://github.com/cc65/cc65.git
114 lines
2.6 KiB
ArmAsm
114 lines
2.6 KiB
ArmAsm
;
|
|
; Ullrich von Bassewitz, 22.06.2002
|
|
;
|
|
; Original C code by Marc 'BlackJack' Rintsch, 19.03.2001
|
|
;
|
|
; int __fastcall__ cbm_read (unsigned char lfn, void* buffer, unsigned int size)
|
|
; /* Reads up to "size" bytes from a file to "buffer".
|
|
; ** Returns the number of actually read bytes, 0 if there are no bytes left
|
|
; ** (EOF) or -1 in case of an error. __oserror contains an errorcode then (see
|
|
; ** table below).
|
|
; */
|
|
; {
|
|
; static unsigned int bytesread;
|
|
; static unsigned char tmp;
|
|
;
|
|
; /* if we can't change to the inputchannel #lfn then return an error */
|
|
; if (__oserror = cbm_k_chkin(lfn)) return -1;
|
|
;
|
|
; bytesread = 0;
|
|
;
|
|
; while (bytesread<size && !cbm_k_readst()) {
|
|
; tmp = cbm_k_basin();
|
|
;
|
|
; /* the kernal routine BASIN sets ST to EOF if the end of file
|
|
; ** is reached the first time, then we have store tmp.
|
|
; ** every subsequent call returns EOF and READ ERROR in ST, then
|
|
; ** we have to exit the loop here immediatly.
|
|
; */
|
|
; if (cbm_k_readst() & 0xBF) break;
|
|
;
|
|
; ((unsigned char*)buffer)[bytesread++] = tmp;
|
|
; }
|
|
;
|
|
; cbm_k_clrch();
|
|
; return bytesread;
|
|
; }
|
|
;
|
|
|
|
.include "cbm.inc"
|
|
|
|
.export _cbm_read
|
|
.importzp ptr1, ptr2, ptr3, tmp1
|
|
.import popax, popa
|
|
.import ___oserror
|
|
|
|
|
|
_cbm_read:
|
|
inx
|
|
stx ptr1+1
|
|
tax
|
|
inx
|
|
stx ptr1 ; Save size with both bytes incremented separately.
|
|
|
|
jsr popax
|
|
sta ptr2
|
|
stx ptr2+1 ; Save buffer
|
|
|
|
jsr popa
|
|
tax
|
|
jsr CHKIN
|
|
bcs @E1 ; Branch on error
|
|
|
|
; bytesread = 0;
|
|
|
|
lda #$00
|
|
sta ptr3
|
|
sta ptr3+1
|
|
beq @L3 ; Branch always
|
|
|
|
; Loop
|
|
|
|
@L1: jsr READST
|
|
cmp #0 ; Status ok?
|
|
bne @L4
|
|
|
|
jsr BASIN ; Read next char from file
|
|
sta tmp1 ; Save it for later
|
|
|
|
jsr READST
|
|
and #$BF
|
|
bne @L4
|
|
|
|
lda tmp1
|
|
ldy #0
|
|
sta (ptr2),y ; Save read byte
|
|
|
|
inc ptr2
|
|
bne @L2
|
|
inc ptr2+1 ; ++buffer;
|
|
|
|
@L2: inc ptr3
|
|
bne @L3
|
|
inc ptr3+1 ; ++bytesread;
|
|
|
|
@L3: dec ptr1
|
|
bne @L1
|
|
dec ptr1+1
|
|
bne @L1
|
|
|
|
@L4: jsr CLRCH
|
|
|
|
lda ptr3
|
|
ldx ptr3+1 ; return bytesread;
|
|
|
|
rts
|
|
|
|
; CHKIN failed
|
|
|
|
@E1: sta ___oserror
|
|
lda #$FF
|
|
tax
|
|
rts ; return -1
|
|
|