Merge pull request #68 from greg-king5/line

Add a stdin console to the Atmos target.

asminc/atmos.inc

@@ -90,6 +90,7 @@ SCREEN          := $BB80
 ; ---------------------------------------------------------------------------
 ; ROM entries
 
+GETLINE         := $C592
 TEXT            := $EC21
 HIRES           := $EC33
 CURSET          := $F0C8

libsrc/atmos/mainargs.s

@@ -1,7 +1,7 @@
 ;
 ; 2003-03-07, Ullrich von Bassewitz
 ; 2011-01-28, Stefan Haubenthal
-; 2013-07-15, Greg King
+; 2013-12-22, Greg King
 ;
 ; Setup arguments for main
 ;
@@ -40,11 +40,21 @@ L0:     lda     CFOUND_NAME,y
 ;
         ldx     #0
 L2:     lda     BASIC_BUF,x
-        beq     done            ; no "rem," no args.
+        beq     done            ; no "rem", no args.
         inx
         cmp     #REM
         bne     L2
-        ldy     #1 * 2
+
+; The arguments must be copied to a safe place because BASIC's input buffer
+; might be re-used by the stdin console.
+
+        ldy     #(SCREEN_XSIZE * 2 - 1) - 1
+L3:     lda     BASIC_BUF,y
+        sta     args,y
+        dey
+        bpl     L3
+
+        ldy     #1 * 2          ; Point to second argv slot
 
 ; Find the next argument
 
@@ -65,12 +75,14 @@ found:  cmp     #'"'            ; Is the argument quoted?
         lda     #' '            ; A space ends the argument
 setterm:sta     term            ; Set end of argument marker
 
-; Now store a pointer to the argument into the next slot. Since the BASIC
-; input buffer is located at the zero page, no calculations are necessary.
+; Now, store a pointer, to the argument, into the next slot.
 
         txa                     ; Get low byte
-        add     #<BASIC_BUF     ; Not at page boundary
+        add     #<args
         sta     argv,y          ; argv[y]= &arg
+        lda     #>0
+        adc     #>args
+        sta     argv+1,y
         iny
         iny
         inc     __argc          ; Found another arg
@@ -88,7 +100,7 @@ argloop:lda     BASIC_BUF,x
 ; replace the terminating character by a zero.
 
         lda     #0
-        sta     BASIC_BUF-1,x
+        sta     args-1,x
 
 ; Check if the maximum number of command line arguments is reached. If not,
 ; parse the next one.
@@ -103,7 +115,6 @@ done:   lda     #<argv
         ldx     #>argv
         sta     __argv
         stx     __argv + 1
-
         rts
 
 .endproc
@@ -115,7 +126,8 @@ done:   lda     #<argv
 .bss
 term:   .res    1
 name:   .res    FNAME_LEN + 1
+args:   .res    SCREEN_XSIZE * 2 - 1
 
 .data
 argv:   .addr   name
-        .res    MAXARGS * 2
+        .res    MAXARGS * 2, 0

libsrc/atmos/read.s

@@ -0,0 +1,85 @@
+;
+; 2013-12-24, Greg King
+;
+; int read (int fd, void* buf, unsigned count);
+;
+; This function is a hack!  It lets us get text from the stdin console.
+;
+
+        .export         _read
+        .constructor    initstdin
+
+        .import         popax
+        .importzp       ptr1, ptr2, ptr3
+
+        .macpack        generic
+        .include        "atmos.inc"
+
+.proc   _read
+
+        sta     ptr3
+        stx     ptr3+1          ; save count as result
+        eor     #$FF
+        sta     ptr2
+        txa
+        eor     #$FF
+        sta     ptr2+1          ; Remember -count-1
+
+        jsr     popax           ; get buf
+        sta     ptr1
+        stx     ptr1+1
+        jsr     popax           ; get fd and discard
+
+L1:     inc     ptr2
+        bnz     L2
+        inc     ptr2+1
+        bze     L9              ; no more room in buf
+
+; If there are no more characters in BASIC's input buffer, then get a line from
+; the console into that buffer.
+
+L2:     ldx     text_count
+        bpl     L3
+        jsr     GETLINE
+        ldx     #<(0 - 1)
+
+L3:     inx
+        lda     BASIC_BUF,x
+        bnz     L4              ; (zero-terminated buffer)
+        ldx     #<-1
+        lda     #$0A            ; return newline char. at end of line
+L4:     stx     text_count
+        ldy     #0
+        sta     (ptr1),y
+        inc     ptr1
+        bnz     L1
+        inc     ptr1+1
+        bnz     L1              ; branch always
+
+; No error, return count.
+
+L9:     lda     ptr3
+        ldx     ptr3+1
+        rts
+
+.endproc
+
+
+;--------------------------------------------------------------------------
+; initstdin:  Reset the stdin console.
+
+.segment        "INIT"
+
+initstdin:
+        ldx     #<-1
+        stx     text_count
+        rts
+
+
+;--------------------------------------------------------------------------
+
+.bss
+
+text_count:
+        .res    1
+