WIP

path.s

@@ -8,6 +8,8 @@
 
         .org $2000
 
+        .include "apple2.inc"
+        .include "apple2.mac"
         .include "prodos.inc"
 
 ;;; ============================================================
@@ -20,7 +22,20 @@ INBUF           := $200         ; GETLN input buffer
 CROUT   := $FD8E
 COUT    := $FDED
 
+MOVE    := $FE2C                ; call with Y=0
+MOVE_SRC   := $3C
+MOVE_END   := $3E
+MOVE_DST   := $42
+
+
+TOKEN_NAME_TABLE := $D0D0
+
+CASE_MASK = $DF
+
 ;;; ============================================================
+;;; Install the new command
+
+        ;; TODO: Fail if Applesoft is not in ROM
 
         ;; Save previous external command address
         lda     EXTRNCMD+1
@@ -28,34 +43,54 @@ COUT    := $FDED
         lda     EXTRNCMD+2
         sta     next_command+1
 
-        ;; Request a 1-page buffer
+        ;; Request a 2-page buffer
-        lda     #1
+        lda     #2
         jsr     GETBUFR
         bcc     :+
         lda     #$C             ; NO BUFFERS AVAILABLE
         rts
-:
+:       sta     new_page        ; A = MSB of new page
-        ;; A = MSB of new page - update absolute addresses
+
-        ;; (aligned to page boundary so only MSB changes)
+        ;; Compute move delta in pages
+        lda     #>handler
+        sec
+        sbc     new_page
+        sta     page_delta
+
+        ;; Relocatable routine is aligned to page boundary so only MSB changes
         ldx     relocation_table
 :       ldy     relocation_table+1,x
+        lda     handler,y
+        clc
+        adc     page_delta
         sta     handler,y
         dex
         bpl     :-
 
+        ;; Relocate
+        lda     #<handler
+        sta     MOVE_SRC
+        lda     #>handler
+        sta     MOVE_SRC+1
+
+        lda     #<handler_end
+        sta     MOVE_END
+        lda     #>handler_end
+        sta     MOVE_END+1
+
+        lda     #0
+        sta     MOVE_DST
+        lda     new_page
+        sta     MOVE_DST+1
+        ldy     #0
+        jsr     MOVE
+
         ;; Install new address in external command address
+        lda     new_page
         sta     EXTRNCMD+2
         lda     #0
         sta     EXTRNCMD+1
 
-        ;; Relocate
-        ldx     #0
-:       lda     handler,x
-        page_num3 := *+2
-        sta     $2100,x         ; self-modified
-        inx
-        bne     :-
-
         ;; Complete
         rts
 
@@ -68,21 +103,19 @@ COUT    := $FDED
         .res    $2100 - *, 0
 
 .proc handler
+        ptr      := $06
 
         ;; Check for this command, character by character.
         ldx     #0
-nxtchr: lda     INBUF,x
+        ;;  TODO: skip leading spaces
 
-        and     #$7F            ; Convert to ASCII
+nxtchr: lda     INBUF,x
-        cmp     #'a'            ; Convert to upper-case
+        page_num6 := *+2         ; address needing updating
-        bcc     :+
+        jsr     to_upper
-        cmp     #'z'+1
-        bcs     :+
-        and     #$DF
 
         page_num1 := *+2         ; address needing updating
-:       cmp     command_string,x
+        cmp     command_string,x
-        bne     not_path
+        bne     check_if_token
         inx
         cpx     #command_length
         bne     nxtchr
@@ -115,15 +148,75 @@ nxtchr: lda     INBUF,x
 
 ;;; ============================================================
 
-not_path:
+check_if_token:
+        ;; Ensure it's alpha
+        lda     INBUF
+        page_num7 := *+2         ; address needing updating
+        jsr     to_upper
 
+        cmp     #'A'|$80
+        bcc     not_ours
+        cmp     #('Z'+1)|$80
+        bcs     not_ours
+
+        ;; Check if it's a BASIC token. Based on the AppleSoft BASIC source.
+
+        ;; Point ptr at TOKEN_NAME_TABLE less one page (will advance below)
+        lda     #<(TOKEN_NAME_TABLE-$100)
+        sta     ptr
+        lda     #>(TOKEN_NAME_TABLE-$100)
+        sta     ptr+1
+
+        ;; These start at "-1" and are immediately incremented
+        ldx     #$FF            ; X = position in input line
+        ldy     #$FF            ; (ptr),y offset TOKEN_NAME_TABLE
+
+        ;; Match loop
+mloop:  iny                     ; Advance through token table
+        bne     :+
+        inc     ptr+1
+:       inx
+
+        ;; Check for match
+next_char:
+        lda     INBUF,x         ; Next character
+        page_num8 := *+2        ; address needing updating
+        jsr     to_upper
+
+        ;; NOTE: Does not skip over spaces, unlike BASIC tokenizer
+
+        sec                     ; Compare by subtraction..
+        sbc     (ptr),Y
+        beq     mloop
+        cmp     #$80          ; If only difference was the high bit
+        beq     not_ours      ; then it's end-of-token -- and a match!
+
+        ;; Otherwise, advance to next token
+next_token:
+        ldx     #0              ; Start next match at start of input line
+        ;; TODO: skip leading spaces
+
+@loop:  lda     (ptr),y         ; Scan table looking for a high bit set
+        iny
+        bne     :+
+        inc     ptr+1
+:       asl
+        bcc     @loop           ; High bit clear, keep looking
+        lda     (ptr),y         ; End of table?
+        bne     next_char       ; Nope, check for a match
+
+        ;; Not a keyword, so invoke
+
+not_a_token:
+        ;; TODO: Implement me!
 
-;;; ============================================================
 not_ours:
         sec                     ; Signal failure...
         next_command := *+1
         jmp     $ffff           ; Execute next command in chain
 
+
+;;; ============================================================
 ;;; ============================================================
 
 execute:
@@ -137,10 +230,10 @@ execute:
         ;; Show current path
 
         ldx     #0
-        page_num3 := *+2
+        page_num3 := *+2         ; address needing updating
 :       cpx     path_buffer
         beq     done
-        page_num4 := *+2
+        page_num4 := *+2         ; address needing updating
         lda     path_buffer+1,x
         ora     #$80
         jsr     COUT
@@ -154,7 +247,6 @@ done:   clc
 ;;; --------------------------------------------------
         ;; Set path
 set_path:
-        ptr := $06
         lda     VPATH1
         sta     ptr
         ldx     VPATH1+1
@@ -164,27 +256,43 @@ set_path:
         lda     (ptr),y
         tay
 :       lda     (ptr),y
-        page_num5 := *+2
+        page_num5 := *+2         ; address needing updating
         sta     path_buffer,y
         dey
         bpl     :-
         clc
         rts
 
+;;; ============================================================
+;;; Helpers
+
+.proc to_upper
+        cmp     #'a'|$80
+        bcc     skip
+        and     #CASE_MASK
+skip:   rts
+.endproc
+
 ;;; ============================================================
 ;;; Data
 
 command_string:
-        .byte   "PATH"        ; Command string
+        scrcode "PATH"
         command_length  =  *-command_string
 
 path_buffer:
         .res    65, 0
 
 .endproc
-        .assert .sizeof(handler) <= $100, error, "Must fit on one page"
+        .assert .sizeof(handler) <= $200, error, "Must fit on two pages"
+        handler_end := *-1
         next_command := handler::next_command
 
+new_page:
+        .byte   0
+page_delta:
+        .byte   0
+
 relocation_table:
         .byte   5
         .byte   <handler::page_num1
@@ -192,3 +300,6 @@ relocation_table:
         .byte   <handler::page_num3
         .byte   <handler::page_num4
         .byte   <handler::page_num5
+        .byte   <handler::page_num6
+        .byte   <handler::page_num7
+        .byte   <handler::page_num8