msbasic/var.s

.segment "CODE"

; ----------------------------------------------------------------------------
; "DIM" STATEMENT
; ----------------------------------------------------------------------------
NXDIM:
        jsr     CHKCOM
DIM:
        tax
        jsr     PTRGET2
        jsr     CHRGOT
        bne     NXDIM
        rts

; ----------------------------------------------------------------------------
; PTRGET -- GENERAL VARIABLE SCAN
;
; SCANS VARIABLE NAME AT TXTPTR, AND SEARCHES THE
; VARTAB AND ARYTAB FOR THE NAME.
; IF NOT FOUND, CREATE VARIABLE OF APPROPRIATE TYPE.
; RETURN WITH ADDRESS IN VARPNT AND Y,A
;
; ACTUAL ACTIVITY CONTROLLED SOMEWHAT BY TWO FLAGS:
;	DIMFLG -- NONZERO IF CALLED FROM "DIM"
;		ELSE = 0
;
;	SUBFLG -- = $00
;		= $40 IF CALLED FROM "GETARYPT"
; ----------------------------------------------------------------------------
PTRGET:
        ldx     #$00
        jsr     CHRGOT
PTRGET2:
        stx     DIMFLG
PTRGET3:
        sta     VARNAM
        jsr     CHRGOT
        jsr     ISLETC
        bcs     NAMOK
SYNERR3:
        jmp     SYNERR
NAMOK:
        ldx     #$00
        stx     VALTYP
.ifndef CONFIG_SMALL
        stx     VALTYP+1
.endif
        jsr     CHRGET
        bcc     L2ECD
        jsr     ISLETC
        bcc     L2ED8
L2ECD:
        tax
L2ECE:
        jsr     CHRGET
        bcc     L2ECE
        jsr     ISLETC
        bcs     L2ECE
L2ED8:
        cmp     #$24
.ifdef CONFIG_SMALL
        bne     L2EF9
.else
        bne     L2EE2
.endif
        lda     #$FF
        sta     VALTYP
.ifndef CONFIG_SMALL
        bne     L2EF2
L2EE2:
        cmp     #$25
        bne     L2EF9
        lda     SUBFLG
        bne     SYNERR3
        lda     #$80
        sta     VALTYP+1
        ora     VARNAM
        sta     VARNAM
L2EF2:
.endif
        txa
        ora     #$80
        tax
        jsr     CHRGET
L2EF9:
        stx     VARNAM+1
        sec
        ora     SUBFLG
        sbc     #$28
        bne     L2F05
        jmp     ARRAY
L2F05:
        lda     #$00
        sta     SUBFLG
        lda     VARTAB
        ldx     VARTAB+1
        ldy     #$00
L2F0F:
        stx     LOWTR+1
L2F11:
        sta     LOWTR
        cpx     ARYTAB+1
        bne     L2F1B
        cmp     ARYTAB
        beq     NAMENOTFOUND
L2F1B:
        lda     VARNAM
        cmp     (LOWTR),y
        bne     L2F29
        lda     VARNAM+1
        iny
        cmp     (LOWTR),y
        beq     SET_VARPNT_AND_YA
        dey
L2F29:
        clc
        lda     LOWTR
        adc     #BYTES_PER_VARIABLE
        bcc     L2F11
        inx
        bne     L2F0F

; ----------------------------------------------------------------------------
; CHECK IF (A) IS ASCII LETTER A-Z
;
; RETURN CARRY = 1 IF A-Z
;	= 0 IF NOT
; ----------------------------------------------------------------------------
ISLETC:
        cmp     #$41
        bcc     L2F3C
        sbc     #$5B
        sec
        sbc     #$A5
L2F3C:
        rts

; ----------------------------------------------------------------------------
; VARIABLE NOT FOUND, SO MAKE ONE
; ----------------------------------------------------------------------------
NAMENOTFOUND:
        pla
        pha
        cmp     #<FRM_VARIABLE_CALL
        bne     MAKENEWVARIABLE
.ifdef CONFIG_SAFE_NAMENOTFOUND
        tsx
        lda     STACK+2,x
        cmp     #>FRM_VARIABLE_CALL
        bne     MAKENEWVARIABLE
.endif
LD015:
        lda     #<C_ZERO
        ldy     #>C_ZERO
        rts

; ----------------------------------------------------------------------------
.ifndef CONFIG_2
C_ZERO:
        .byte   $00,$00
.endif

; ----------------------------------------------------------------------------
; MAKE A NEW SIMPLE VARIABLE
;
; MOVE ARRAYS UP 7 BYTES TO MAKE ROOM FOR NEW VARIABLE
; ENTER 7-BYTE VARIABLE DATA IN THE HOLE
; ----------------------------------------------------------------------------
MAKENEWVARIABLE:
.ifdef CONFIG_CBM_ALL
        lda     VARNAM
        ldy     VARNAM+1
        cmp     #$54
        bne     LD02F
        cpy     #$C9
        beq     LD015
        cpy     #$49
        bne     LD02F
LD02C:
        jmp     SYNERR
LD02F:
        cmp     #$53
        bne     LD037
        cpy     #$54
        beq     LD02C
LD037:
.endif
        lda     ARYTAB
        ldy     ARYTAB+1
        sta     LOWTR
        sty     LOWTR+1
        lda     STREND
        ldy     STREND+1
        sta     HIGHTR
        sty     HIGHTR+1
        clc
        adc     #BYTES_PER_VARIABLE
        bcc     L2F68
        iny
L2F68:
        sta     HIGHDS
        sty     HIGHDS+1
        jsr     BLTU
        lda     HIGHDS
        ldy     HIGHDS+1
        iny
        sta     ARYTAB
        sty     ARYTAB+1
        ldy     #$00
        lda     VARNAM
        sta     (LOWTR),y
        iny
        lda     VARNAM+1
        sta     (LOWTR),y
        lda     #$00
        iny
        sta     (LOWTR),y
        iny
        sta     (LOWTR),y
        iny
        sta     (LOWTR),y
        iny
        sta     (LOWTR),y
.ifndef CONFIG_SMALL
        iny
        sta     (LOWTR),y
.endif

; ----------------------------------------------------------------------------
; PUT ADDRESS OF VALUE OF VARIABLE IN VARPNT AND Y,A
; ----------------------------------------------------------------------------
SET_VARPNT_AND_YA:
        lda     LOWTR
        clc
        adc     #$02
        ldy     LOWTR+1
        bcc     L2F9E
        iny
L2F9E:
        sta     VARPNT
        sty     VARPNT+1
        rts