mirror of
https://github.com/cc65/cc65.git
synced 2024-11-17 09:07:32 +00:00
bfdfd83fde
different calling conventions. git-svn-id: svn://svn.cc65.org/cc65/trunk@3038 b7a2c559-68d2-44c3-8de9-860c34a00d81
220 lines
3.5 KiB
ArmAsm
220 lines
3.5 KiB
ArmAsm
;
|
|
; Christian Groessler, May 2002
|
|
;
|
|
; this file provides the lseek() function
|
|
;
|
|
; off_t __fastcall__ lseek(int fd, off_t offset, int whence);
|
|
;
|
|
|
|
|
|
.export _lseek
|
|
.import incsp6,__oserror
|
|
.import __inviocb,ldax0sp,ldaxysp,fdtoiocb
|
|
.import __dos_type
|
|
.import fd_table
|
|
.importzp sreg,ptr1,ptr2,ptr3,ptr4
|
|
.importzp tmp1,tmp2,tmp3
|
|
.include "atari.inc"
|
|
.include "errno.inc"
|
|
.include "fd.inc"
|
|
|
|
; seeking not supported, return -1 and ENOSYS errno value
|
|
no_supp:jsr incsp6
|
|
lda #<ENOSYS
|
|
jsr __seterrno ; set __errno, return zero in A
|
|
sta __oserror
|
|
lda #$FF
|
|
tax
|
|
sta sreg
|
|
sta sreg+1
|
|
rts
|
|
|
|
parmerr:
|
|
iocberr:jsr incsp6
|
|
ldx #255
|
|
stx sreg
|
|
stx sreg+1
|
|
jmp __inviocb
|
|
|
|
|
|
; lseek() entry point
|
|
|
|
.proc _lseek
|
|
|
|
cpx #0 ; sanity check whence parameter
|
|
bne parmerr
|
|
cmp #3 ; valid values are 0..2
|
|
bcs parmerr
|
|
sta tmp1 ; remember whence
|
|
|
|
ldy #5
|
|
jsr ldaxysp ; get fd
|
|
jsr fdtoiocb ; convert to iocb in A, fd_table index in X
|
|
bmi iocberr
|
|
sta tmp3 ; remember iocb
|
|
|
|
jsr chk_supp ; check, whether seeking is supported by DOS/Disk
|
|
bcc no_supp
|
|
|
|
ldx tmp1 ; whence
|
|
beq cur
|
|
dex
|
|
beq end
|
|
|
|
; SEEK_SET
|
|
dex
|
|
stx ptr3
|
|
stx ptr3+1
|
|
stx ptr4
|
|
stx ptr4+1
|
|
beq cont
|
|
|
|
; SEEK_CUR
|
|
cur: ldx tmp3
|
|
lda #38 ; NOTE
|
|
sta ICCOM,x
|
|
jsr CIOV ; read it
|
|
bmi xxerr
|
|
l01: lda ICAX3,x ; low byte of position
|
|
sta ptr3
|
|
lda ICAX4,x ; med byte of position
|
|
sta ptr3+1
|
|
lda ICAX5,x ; high byte of position
|
|
sta ptr4
|
|
lda #0
|
|
sta ptr4+1
|
|
beq cont
|
|
|
|
; SEEK_END
|
|
end: ldx tmp3
|
|
lda #39 ; get file size
|
|
sta ICCOM,x
|
|
jsr CIOV
|
|
bpl l01
|
|
|
|
; error returned from CIO
|
|
xxerr: sty __oserror
|
|
bmi iocberr
|
|
|
|
; check for offset 0, SEEK_CUR (get current position)
|
|
cont: ldy #3
|
|
jsr ldaxysp ; get upper word
|
|
sta ptr1
|
|
stx ptr1+1
|
|
jsr ldax0sp ; get lower word
|
|
stx tmp2
|
|
ora tmp2
|
|
ora ptr1
|
|
ora ptr1+1
|
|
bne seek
|
|
lda tmp1 ; whence (0 = SEEK_CUR)
|
|
bne seek
|
|
|
|
; offset 0, SEEK_CUR: return current fp
|
|
ret: jsr incsp6
|
|
|
|
lda ptr4+1
|
|
sta sreg+1
|
|
lda ptr4
|
|
sta sreg
|
|
ldx ptr3+1
|
|
lda ptr3
|
|
|
|
.if 0
|
|
; return exactly the position DOS has
|
|
ldx tmp3
|
|
lda #38 ; NOTE
|
|
sta ICCOM,x
|
|
jsr CIOV ; read it
|
|
bmi xxerr
|
|
lda #0
|
|
sta sreg+1
|
|
lda ICAX5,x ; high byte of position
|
|
sta sreg
|
|
lda ICAX3,x ; low byte of position
|
|
pha
|
|
lda ICAX4,x ; med byte of position
|
|
tax
|
|
pla
|
|
.endif
|
|
|
|
rts
|
|
|
|
parmerr1: jmp parmerr
|
|
|
|
; we have to call POINT
|
|
seek: jsr ldax0sp ; get lower word of new offset
|
|
clc
|
|
adc ptr3
|
|
sta ptr3
|
|
txa
|
|
adc ptr3+1
|
|
sta ptr3+1
|
|
lda ptr1
|
|
adc ptr4
|
|
sta ptr4
|
|
lda ptr1+1
|
|
adc ptr4+1
|
|
sta ptr4+1
|
|
bne parmerr1 ; resulting value too large
|
|
|
|
ldx tmp3 ; IOCB
|
|
lda ptr3
|
|
sta ICAX3,x
|
|
lda ptr3+1
|
|
sta ICAX4,x
|
|
lda ptr4
|
|
sta ICAX5,x
|
|
lda #37 ;POINT
|
|
sta ICCOM,x
|
|
jsr CIOV
|
|
bpl ret
|
|
bmi xxerr
|
|
|
|
.endproc
|
|
|
|
; check, whether seeking is supported
|
|
; tmp3: iocb
|
|
; X: index into fd_table
|
|
;
|
|
; On non-SpartaDOS, seeking is not supported.
|
|
; We check, whether CIO function 39 (get file size) returns OK.
|
|
; If yes, NOTE and POINT work with real file offset.
|
|
; If not, NOTE and POINT work with the standard ScNum/Offset values.
|
|
; We remember a successful check in fd_table.ft_flag, bit 3.
|
|
|
|
chk_supp:
|
|
lda fd_table+ft_flag,x
|
|
and #8
|
|
bne supp
|
|
|
|
; do the test
|
|
lda __dos_type
|
|
cmp #SPARTADOS
|
|
bne ns1
|
|
txa
|
|
pha
|
|
lda DOS+1 ; get SpartaDOS version
|
|
cmp #$40
|
|
bcs supp1 ; SD-X (ver 4.xx) supports seeking on all disks
|
|
ldx tmp3 ; iocb to use
|
|
lda #39 ; get file size
|
|
sta ICCOM,x
|
|
jsr CIOV
|
|
bmi notsupp ; error code ? should be 168 (invalid command)
|
|
|
|
; seeking is supported on this DOS/Disk combination
|
|
|
|
supp1: pla
|
|
tax
|
|
lda #8
|
|
ora fd_table+ft_flag,x
|
|
sta fd_table+ft_flag,x
|
|
supp: sec
|
|
rts
|
|
|
|
notsupp:pla
|
|
ns1: clc
|
|
rts
|
|
|