implement SIO handler

diff --git a/libsrc/atari/shadow_ram_handlers.s b/libsrc/atari/shadow_ram_handlers.s
index 1edc82d5153fb07a136319a46b343489fb8ea4e8..048a5a5c05a994d8270c77c1129fefcdef1cb3e2 100644 (file)
--- a/libsrc/atari/shadow_ram_handlers.s
+++ b/libsrc/atari/shadow_ram_handlers.s
@@ -16,9 +16,7 @@ DEBUG =       1
        .export         sram_init
        .export         KEYBDV_wrapper
 
-BUFSZ          =       128
-BUFSZ_CIO      =       BUFSZ
-BUFSZ_SIO      =       BUFSZ
+BUFSZ          =       256             ; bounce buffer size
 
 .macro disable_rom
        lda     PORTB
@@ -39,8 +37,6 @@ BUFSZ_SIO     =       BUFSZ
 
 .segment "INIT"
 
-;enable_count: .res    1
-
 ; Turn off ROMs, install system and interrupt wrappers, set new chargen pointer
 
 sram_init:
@@ -98,8 +94,7 @@ zpptr1:       .res    2
 .segment "LOWBUFS"
 
 ; bounce buffers for CIO and SIO calls
-CIO_buffer:    .res    BUFSZ_CIO
-SIO_buffer:    .res    BUFSZ_SIO
+bounce_buffer: .res    BUFSZ
 
 
 .segment "LOWCODE"
@@ -193,7 +188,7 @@ CIO_filename:
        jsr     setup_zpptr1_y0
        jsr     copy_filename
 CIO_fn_cont:
-       jsr     ciobuf_to_iocb
+       jsr     bncbuf_to_iocb
        ldy     CIO_y
        jsr     CIO_call_a              ; call CIO (maybe A isn't needed, then we could call CIO_call)
        php
@@ -214,6 +209,7 @@ CIO_filename2:
        jmp     CIO_fn_cont
 
 
+; enable ROM, call CIO, disable ROM
 
 CIO_call_a:
        lda     CIO_a
@@ -292,14 +288,14 @@ CIO_read:
        lda     ICBLH,x                 ; get high byte of length
        bne     big_read                ; not zero -> data too large for our buffers
                                        ; CHANGE HERE TO SUPPORT BOUNCE BUFFERS > 255 BYTES
-       lda     #<BUFSZ_CIO
+       lda     #<BUFSZ
        cmp     ICBLL,x
        bcc     big_read
 
 ; Data size fits into bounce buffer
 
        jsr     setup_zpptr1
-       jsr     ciobuf_to_iocb
+       jsr     bncbuf_to_iocb
        jsr     CIO_call_a              ; call CIO
        php
        bpl     @no_err
@@ -332,15 +328,15 @@ big_read:
        jsr     iocblen_to_orig_len
        jsr     iocbptr_to_orig_ptr
        jsr     setup_zpptr1
-       jsr     ciobuf_to_iocb          ; let ICBAL/ICBAH point to bounce buffer
+       jsr     bncbuf_to_iocb          ; let ICBAL/ICBAH point to bounce buffer
 
 br_loop:
-       jsr     cmp_orig_len_cio_bufsz  ; is transfer length > bounce buffer size?
+       jsr     cmp_orig_len_bnc_bufsz  ; is transfer length > bounce buffer size?
        bcs     br_last                 ; no, last transfer, use remaining size
 
-       lda     #>BUFSZ_CIO
+       lda     #>BUFSZ
        sta     ICBLH,x                 ; set data length
-       lda     #<BUFSZ_CIO
+       lda     #<BUFSZ
        sta     ICBLL,x
        bne     br_cont
 
@@ -452,7 +448,7 @@ CIO_write:
        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
+       lda     #<BUFSZ
        cmp     ICBLL,x
        bcc     big_write
 
@@ -460,7 +456,7 @@ CIO_write:
 ; Data size fits into bounce buffer
 
        jsr     setup_zpptr1
-       jsr     ciobuf_to_iocb
+       jsr     bncbuf_to_iocb
        jsr     copy_from_user
        ldy     CIO_y
        jsr     CIO_call_a
@@ -481,15 +477,15 @@ big_write:
        jsr     iocblen_to_orig_len
        jsr     iocbptr_to_orig_ptr
        jsr     setup_zpptr1
-       jsr     ciobuf_to_iocb          ; let ICBAL/ICBAH point to bounce buffer
+       jsr     bncbuf_to_iocb          ; let ICBAL/ICBAH point to bounce buffer
 
 bw_loop:
-       jsr     cmp_orig_len_cio_bufsz  ; is transfer length > bounce buffer size?
+       jsr     cmp_orig_len_bnc_bufsz  ; is transfer length > bounce buffer size?
        bcs     bw_last                 ; no, last transfer, use remaining size
 
-       lda     #>BUFSZ_CIO
+       lda     #>BUFSZ
        sta     ICBLH,x                 ; set data length
-       lda     #<BUFSZ_CIO
+       lda     #<BUFSZ
        sta     ICBLL,x
        bne     bw_cont
 
@@ -577,11 +573,11 @@ bw_done:
 ; input:   orig_len - length
 ; output:         A - destroyed
 ;                CF - 0/1 for larger/not larger
-cmp_orig_len_cio_bufsz:
+cmp_orig_len_bnc_bufsz:
        sec
-       lda     #<BUFSZ_CIO
+       lda     #<BUFSZ
        sbc     orig_len
-       lda     #>BUFSZ_CIO
+       lda     #>BUFSZ
        sbc     orig_len+1
        rts
 
@@ -595,7 +591,7 @@ copy_to_user:
        ldy     ICBLL,x                 ; get # of bytes read (CHANGE HERE TO SUPPORT BOUNCE BUFFERS > 255 BYTES)
        beq     @copy_done
 @copy: dey
-       lda     CIO_buffer,y
+       lda     bounce_buffer,y
        sta     (zpptr1),y
        cpy     #0
        bne     @copy
@@ -613,7 +609,7 @@ copy_from_user:
        beq     @copy_done
 @copy: dey
        lda     (zpptr1),y
-       sta     CIO_buffer,y
+       sta     bounce_buffer,y
        cpy     #0
        bne     @copy
 @copy_done:
@@ -667,21 +663,21 @@ restore_icba:
 ; put bounce buffer address into ICBAL/ICBAH
 ; input:   X - IOCB index
 ; output:  A - destroyed
-ciobuf_to_iocb:
-       lda     #<CIO_buffer
+bncbuf_to_iocb:
+       lda     #<bounce_buffer
        sta     ICBAL,x
-       lda     #>CIO_buffer
+       lda     #>bounce_buffer
        sta     ICBAH,x
        rts
 
 
-; copy file name pointed to by 'zpptr1' to bounce buffer 'CIO_buffer'
-; input:   Y - index into file name buffer and CIO_buffer
+; copy file name pointed to by 'zpptr1' to 'bounce_buffer'
+; input:   Y - index into file name buffer and bounce_buffer
 ; output:  Y - points to first invalid byte after file name
 ;          A - destroyed
 copy_filename:
        lda     (zpptr1),y
-       sta     CIO_buffer,y
+       sta     bounce_buffer,y
        beq     copy_fn_done
        iny
        cmp     #ATEOL
@@ -706,12 +702,35 @@ setup_zpptr1:
 
 ;---------------------------------------------------------
 
+; SIO handler
+; We only handle SIO_STAT, SIO_READ, SIO_WRITE, and SIO_WRITEV.
+; These are the only functions used by the runtime library currently.
+; For other function we return NVALID status code.
+
 my_SIOV:
-       pha
+       lda     DCOMND                  ; get command
+       cmp     #SIO_STAT
+       beq     SIO_stat
+       cmp     #SIO_READ
+       beq     SIO_read
+       cmp     #SIO_WRITE
+       beq     SIO_write
+       cmp     #SIO_WRITEV
+       beq     SIO_write
+
+       ; unhandled command
+       lda     #NVALID
+SIO_err:sta    DSTATS
+       rts
+
+; SIO_STAT is always called with a low buffer (by the runtime)
+SIO_stat:
+       ; fall thru
+
+SIO_call:
        lda     PORTB
        sta     cur_SIOV_PORTB
        enable_rom
-       pla
        jsr     SIOV_org
        php
        pha
@@ -721,6 +740,132 @@ my_SIOV:
        plp
        rts
 
+
+; SIO read handler
+; ----------------
+
+SIO_read:
+
+; @@@ TODO: check if bounce buffer is really needed because buffer is in ROM area
+
+; we only support transfers <= bounce buffer size
+       jsr     cmp_sio_len_bnc_bufsz
+       bcs     sio_read_len_ok
+
+       lda     #DERROR         ; don't know a better status code for this
+       bne     SIO_err
+
+sio_read_len_ok:
+       lda     DBUFLO
+       sta     zpptr1          ; remember destination buffer address
+       lda     DBUFHI
+       sta     zpptr1+1
+
+       jsr     bncbuf_to_dbuf  ; put bounce buffer address to DBUFLO/DBUFHI
+
+       jsr     SIO_call        ; do the operation
+       pha
+       lda     DSTATS          ; get status
+       bmi     sio_read_ret    ; error
+
+       ; copy data to user buffer
+sio_read_ok:
+       lda     DBYTHI          ; could be 1 for 256 bytes
+       beq     srok1
+       ldy     #0
+       beq     srok2
+srok1: ldy     DBYTLO
+srok2: dey
+sio_read_copy:
+       lda     bounce_buffer,y
+       sta     (zpptr1),y
+       dey
+       cpy     #$ff
+       bne     sio_read_copy
+
+sio_read_ret:
+       jsr     orgbuf_to_dbuf
+
+       pla
+       rts                     ; success return
+
+
+; SIO write handler
+; -----------------
+
+SIO_write:
+
+; @@@ TODO: check if bounce buffer is really needed because buffer is in ROM area
+
+; we only support transfers <= bounce buffer size
+       jsr     cmp_sio_len_bnc_bufsz
+       bcs     sio_write_len_ok
+
+       lda     #DERROR         ; don't know a better status code for this
+       bne     SIO_err
+
+sio_write_len_ok:
+       lda     DBUFLO
+       sta     zpptr1          ; get source buffer address
+       lda     DBUFHI
+       sta     zpptr1+1
+
+       ; copy data from user buffer to bounce buffer
+       lda     DBYTHI          ; could be 1 for 256 bytes
+       beq     swok1
+       ldy     #0
+       beq     swok2
+swok1: ldy     DBYTLO
+swok2: dey
+sio_write_copy:
+       lda     (zpptr1),y
+       sta     bounce_buffer,y
+       dey
+       cpy     #$ff
+       bne     sio_write_copy
+
+       jsr     bncbuf_to_dbuf  ; put bounce buffer address to DBUFLO/DBUFHI
+
+       jsr     SIO_call        ; do the operation
+       pha
+       jsr     orgbuf_to_dbuf
+       pla
+       rts
+
+
+; check if SIO length is larger than bounce buffer size
+; input:   orig_len - length
+; output:         A - destroyed
+;                CF - 0/1 for larger/not larger
+cmp_sio_len_bnc_bufsz:
+       sec
+       lda     #<BUFSZ
+       sbc     DBYTLO
+       lda     #>BUFSZ
+       sbc     DBYTHI
+       rts
+
+; put bounce buffer address into DBUFLO/DBUFHI
+; input:   (--)
+; output:  A - destroyed
+bncbuf_to_dbuf:
+       lda     #<bounce_buffer
+       sta     DBUFLO
+       lda     #>bounce_buffer
+       sta     DBUFHI
+       rts
+
+; put original buffer address into DBUFLO/DBUFHI
+; input:   zpptr1 - original pointer
+; output:  A      - destroyed
+orgbuf_to_dbuf:
+       lda     zpptr1
+       sta     DBUFLO
+       lda     zpptr1+1
+       sta     DBUFHI
+       rts
+
+
 ;---------------------------------------------------------
 
 KEYBDV_wrapper: