.segment "EXTZP" : zeropage
zpptr1: .res 2
-zpptr2: .res 2
+;zpptr2: .res 2
.segment "LOWBUFS"
rts
-
-
-CIO_write:
- lda ICBLL,x
- ora ICBLH,x
- beq CIO_call_a ; special I/O through A register in case buffer length is 0
-
- ;...
- bne CIO_call_a
-
-
; CIO handler
; We have buffer pointer and length entries in the IOCB, but their
; usage depends on the function.
my_CIOV:
- ;jmp CIOV_call
- ;brk
-
; @@@ TODO: check X for valid IOCB index ((X < $80) and ((X & $F) == 0))
sta CIO_a
cmp #PUTREC
bcc CIO_read ; input (GETREC or GETCHR)
cmp #CLOSE
- bcc CIO_write ; output (PUTREC or PUTCHR)
+ bcc CIO_write_jmp ; output (PUTREC or PUTCHR)
beq CIO_call_a ; pass through, buffer not used
cmp #RENAME ; 2 filenames as input parameters in buffer, length not used
beq CIO_filename2
bcs CIO_call_a ; other commands: assume no buffer
; not reached
+CIO_write_jmp:
+ jmp CIO_write
+
+
+; READ handler
+; ------------
CIO_read:
lda ICBLL,x
ora ICBLH,x
beq CIO_call_a ; special I/O through A register in case buffer length is 0
+; @@@ TODO: check if bounce buffer is really needed because buffer is in ROM area
+
; If the data length is larger than our bounce buffer, we have to split the request into smaller ones.
; Otherwise we can get away with one call and a copy to the final destination afterwards.
jsr ciobuf_to_iocb
jsr CIO_call_a ; call CIO
php
- bpl no_err
+ bpl @no_err
cpy #EOFERR
- beq no_err
+ beq @no_err
pha
jsr restore_icba
pla
plp
rts ; return with error
-no_err:
+@no_err:
sta CIO_a
sty CIO_y
bne br_done
; update user buffer pointer (zpptr1)
+ clc
lda zpptr1
adc ICBLL,x
sta zpptr1
+CIO_call_a_jmp:
+ jmp CIO_call_a
+
+
+
+; WRITE handler
+; -------------
+
+
+CIO_write:
+ lda ICBLL,x
+ ora ICBLH,x
+ beq CIO_call_a_jmp ; special I/O through A register in case buffer length is 0
+
+; @@@ TODO: check if bounce buffer is really needed because buffer is in ROM area
+
+; If the data length is larger than our bounce buffer, we have to split the request into smaller ones.
+; Otherwise we can get away with a copy to the bounce buffer and the call.
+
+ lda ICBLH,x ; get high byte of length
+ bne big_write ; not zero -> data too large for our buffers
+ ; CHANGE HERE TO SUPPORT BOUNCE BUFFERS > 255 BYTES
+ lda #<BUFSZ_CIO
+ cmp ICBLL,x
+ bcc big_write
+
+
+; Data size fits into bounce buffer
+
+ jsr setup_zpptr1
+ jsr ciobuf_to_iocb
+ jsr copy_from_user
+ ldy CIO_y
+ jsr CIO_call_a
+ php
+ pha
+ jsr restore_icba
+ pla
+ plp
+ rts ; return to application
+
+
+; Data size does not fit into bounce buffer
+
+big_write:
+ lda #0
+ sta retlen ; initialize return length
+ sta retlen+1
+ jsr iocblen_to_orig_len
+ jsr iocbptr_to_orig_ptr
+ jsr setup_zpptr1
+ jsr ciobuf_to_iocb ; let ICBAL/ICBAH point to bounce buffer
+
+bw_loop:
+ jsr cmp_orig_len_cio_bufsz ; is transfer length > bounce buffer size?
+ bcs bw_last ; no, last transfer, use remaining size
+
+ lda #>BUFSZ_CIO
+ sta ICBLH,x ; set data length
+ lda #<BUFSZ_CIO
+ sta ICBLL,x
+ bne bw_cont
+
+bw_last:
+ lda orig_len+1
+ sta ICBLH,x ; set data length
+ lda orig_len
+ sta ICBLL,x
+
+bw_cont:
+ sta req_len ; remember length of this request
+ lda ICBLH,x
+ sta req_len+1
+ jsr copy_from_user
+ jsr CIO_call_a ; do the request
+ php
+ bpl bw_no_err
+
+ plp
+ rts ; error return
+
+bw_no_err:
+ sta CIO_a
+ sty CIO_y
+ pla
+ sta CIO_p
+
+; update retlen
+ clc
+ lda retlen
+ adc ICBLL,x
+ sta retlen
+ lda retlen+1
+ adc #0
+ sta retlen+1
+
+; if the request wrote less bytes than requested, we're done
+ lda ICBLL,x
+ cmp req_len
+ bne bw_done
+ lda ICBLH,x
+ cmp req_len+1
+ bne bw_done
+
+; update user buffer pointer (zpptr1)
+ clc
+ lda zpptr1
+ adc ICBLL,x
+ sta zpptr1
+ lda zpptr1+1
+ adc #0
+ sta zpptr1+1
+
+; update remaining length
+ sec
+ lda orig_len
+ sbc ICBLL,x
+ sta orig_len
+ lda orig_len+1
+ sbc #0
+ sta orig_len+1
+
+; still something left to do (remaining length != 0)?
+ lda orig_len
+ ora orig_len+1
+ beq bw_done
+ jmp bw_loop
+
+bw_done:
+ lda retlen
+ sta ICBLL,x
+ lda retlen+1
+ sta ICBLH,x
+ jsr orig_ptr_to_iocbptr
+ lda CIO_p
+ pha
+ lda CIO_a
+ ldy CIO_y
+ plp
+ rts ; return with success
+
+
+
; check if length is larger than bounce buffer size
; input: orig_len - length
; output: A - destroyed
; Y - 0
copy_to_user:
ldy ICBLL,x ; get # of bytes read (CHANGE HERE TO SUPPORT BOUNCE BUFFERS > 255 BYTES)
- beq copy_done
-copy: dey
+ beq @copy_done
+@copy: dey
lda CIO_buffer,y
sta (zpptr1),y
cpy #0
- bne copy
-copy_done:
+ bne @copy
+@copy_done:
+ rts
+
+
+; copy data from user buffer into bounce buffer
+; input: X - IOCB index
+; zpptr1 - pointer to user buffer
+; output: A - destroyed
+; Y - 0
+copy_from_user:
+ ldy ICBLL,x ; get # of bytes to write (CHANGE HERE TO SUPPORT BOUNCE BUFFERS > 255 BYTES)
+ beq @copy_done
+@copy: dey
+ lda (zpptr1),y
+ sta CIO_buffer,y
+ cpy #0
+ bne @copy
+@copy_done:
rts
projects / cc65 / commitdiff