mirror of
https://github.com/cc65/cc65.git
synced 2024-11-17 09:07:32 +00:00
145 lines
3.2 KiB
ArmAsm
145 lines
3.2 KiB
ArmAsm
;
|
|
; Ullrich von Bassewitz, 16.11.2002
|
|
;
|
|
; int read (int fd, void* buf, unsigned count);
|
|
;
|
|
|
|
.export _read
|
|
.constructor initstdin
|
|
|
|
.import SETLFS, OPEN, CHKIN, BASIN, CLRCH, READST
|
|
.import rwcommon
|
|
.import popax
|
|
.import __oserror
|
|
.importzp ptr1, ptr2, ptr3, tmp1, tmp2, tmp3
|
|
|
|
.include "fcntl.inc"
|
|
.include "cbm.inc"
|
|
.include "filedes.inc"
|
|
|
|
|
|
;--------------------------------------------------------------------------
|
|
; initstdin: Open the stdin file descriptors for the keyboard
|
|
|
|
.segment "INIT"
|
|
|
|
.proc initstdin
|
|
|
|
lda #LFN_READ
|
|
sta fdtab+STDIN_FILENO
|
|
lda #STDIN_FILENO + LFN_OFFS
|
|
ldx #CBMDEV_KBD
|
|
stx unittab+STDIN_FILENO
|
|
ldy #$FF
|
|
jsr SETLFS
|
|
jmp OPEN ; Will always succeed
|
|
|
|
.endproc
|
|
|
|
;--------------------------------------------------------------------------
|
|
; _read
|
|
|
|
.code
|
|
|
|
.proc _read
|
|
|
|
jsr rwcommon ; Pop params, check handle
|
|
bcs errout ; Invalid handle, errno already set
|
|
|
|
; Check if the LFN is valid and the file is open for writing
|
|
|
|
adc #LFN_OFFS ; Carry is already clear
|
|
tax
|
|
lda fdtab-LFN_OFFS,x; Get flags for this handle
|
|
and #LFN_READ ; File open for writing?
|
|
beq notopen
|
|
|
|
; Check the EOF flag. If it is set, don't read anything
|
|
|
|
lda fdtab-LFN_OFFS,x; Get flags for this handle
|
|
bmi eof
|
|
|
|
; Valid lfn. Make it the input file
|
|
|
|
jsr CHKIN
|
|
bcs error
|
|
|
|
; Go looping...
|
|
|
|
bcc @L3 ; Branch always
|
|
|
|
; Read the next byte
|
|
|
|
@L0: jsr BASIN
|
|
sta tmp1 ; Save the input byte
|
|
|
|
jsr READST ; Read the IEEE status
|
|
sta tmp3 ; Save it
|
|
and #%10111111 ; Check anything but the EOI bit
|
|
bne error5 ; Assume device not present
|
|
|
|
; Store the byte just read
|
|
|
|
ldy #0
|
|
lda tmp1
|
|
sta (ptr2),y
|
|
inc ptr2
|
|
bne @L1
|
|
inc ptr2+1 ; *buf++ = A;
|
|
|
|
; Increment the byte count
|
|
|
|
@L1: inc ptr3
|
|
bne @L2
|
|
inc ptr3+1
|
|
|
|
; Get the status again and check the EOI bit
|
|
|
|
@L2: lda tmp3
|
|
and #%01000000 ; Check for EOI
|
|
bne @L4 ; Jump if end of file reached
|
|
|
|
; Decrement the count
|
|
|
|
@L3: inc ptr1
|
|
bne @L0
|
|
inc ptr1+1
|
|
bne @L0
|
|
beq done ; Branch always
|
|
|
|
; Set the EOI flag and bail out
|
|
|
|
@L4: ldx tmp2 ; Get the handle
|
|
lda #LFN_EOF
|
|
ora fdtab,x
|
|
sta fdtab,x
|
|
|
|
; Read done, close the input channel
|
|
|
|
done: jsr CLRCH
|
|
|
|
; Return the number of chars read
|
|
|
|
eof: lda ptr3
|
|
ldx ptr3+1
|
|
rts
|
|
|
|
; Error entry, file is not open
|
|
|
|
notopen:
|
|
lda #3 ; File not open
|
|
bne error
|
|
|
|
; Error entry, status not ok
|
|
|
|
error5: lda #5 ; Device not present
|
|
error: sta __oserror
|
|
errout: lda #$FF
|
|
tax ; Return -1
|
|
rts
|
|
|
|
.endproc
|
|
|
|
|
|
|