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flow1.s
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.segment "CODE"
; ----------------------------------------------------------------------------
; "FOR" STATEMENT
;
; FOR PUSHES 18 BYTES ON THE STACK:
; 2 -- TXTPTR
; 2 -- LINE NUMBER
; 5 -- INITIAL (CURRENT) FOR VARIABLE VALUE
; 1 -- STEP SIGN
; 5 -- STEP VALUE
; 2 -- ADDRESS OF FOR VARIABLE IN VARTAB
; 1 -- FOR TOKEN ($81)
; ----------------------------------------------------------------------------
FOR:
lda #$80
sta SUBFLG
jsr LET
jsr GTFORPNT
bne L2619
txa
adc #FOR_STACK1
tax
txs
L2619:
pla
pla
lda #FOR_STACK2
jsr CHKMEM
jsr DATAN
clc
tya
adc TXTPTR
pha
lda TXTPTR+1
adc #$00
pha
lda CURLIN+1
pha
lda CURLIN
pha
lda #TOKEN_TO
jsr SYNCHR
jsr CHKNUM
jsr FRMNUM
lda FACSIGN
ora #$7F
and FAC+1
sta FAC+1
lda #<STEP
ldy #>STEP
sta INDEX
sty INDEX+1
jmp FRM_STACK3
; ----------------------------------------------------------------------------
; "STEP" PHRASE OF "FOR" STATEMENT
; ----------------------------------------------------------------------------
STEP:
lda #<CON_ONE
ldy #>CON_ONE
jsr LOAD_FAC_FROM_YA
jsr CHRGOT
cmp #TOKEN_STEP
bne L2665
jsr CHRGET
jsr FRMNUM
L2665:
jsr SIGN
jsr FRM_STACK2
lda FORPNT+1
pha
lda FORPNT
pha
lda #$81
pha
; ----------------------------------------------------------------------------
; PERFORM NEXT STATEMENT
; ----------------------------------------------------------------------------
NEWSTT:
jsr ISCNTC
lda TXTPTR
ldy TXTPTR+1
.if .def(CONFIG_NO_INPUTBUFFER_ZP) && .def(CONFIG_2)
cpy #>INPUTBUFFER
.ifdef CBM2
nop
.endif
beq LC6D4
.else
; BUG on AppleSoft I,
; fixed differently on AppleSoft II (ldx/inx)
beq L2683
.endif
sta OLDTEXT
sty OLDTEXT+1
LC6D4:
ldy #$00
L2683:
lda (TXTPTR),y
.ifndef CONFIG_11
beq LA5DC ; old: 1 cycle more on generic case
cmp #$3A
beq NEWSTT2
SYNERR1:
jmp SYNERR
LA5DC:
.else
bne COLON; new: 1 cycle more on ":" case
.endif
ldy #$02
lda (TXTPTR),y
clc
.ifdef CONFIG_2
jeq L2701
.else
beq L2701
.endif
iny
lda (TXTPTR),y
sta CURLIN
iny
lda (TXTPTR),y
sta CURLIN+1
tya
adc TXTPTR
sta TXTPTR
bcc NEWSTT2
inc TXTPTR+1
NEWSTT2:
jsr CHRGET
jsr EXECUTE_STATEMENT
jmp NEWSTT
; ----------------------------------------------------------------------------
; EXECUTE A STATEMENT
;
; (A) IS FIRST CHAR OF STATEMENT
; CARRY IS SET
; ----------------------------------------------------------------------------
EXECUTE_STATEMENT:
.ifndef CONFIG_11A
beq RET1
.else
beq RET2
.endif
.ifndef CONFIG_11
sec
.endif
EXECUTE_STATEMENT1:
sbc #$80
.ifndef CONFIG_11
jcc LET ; old: 1 cycle more on instr.
.else
bcc LET1; new: 1 cycle more on assignment
.endif
cmp #NUM_TOKENS
.ifdef CONFIG_2
bcs LC721
.else
bcs SYNERR1
.endif
asl a
tay
lda TOKEN_ADDRESS_TABLE+1,y
pha
lda TOKEN_ADDRESS_TABLE,y
pha
jmp CHRGET
.ifdef CONFIG_11
LET1:
jmp LET
COLON:
cmp #$3A
beq NEWSTT2
SYNERR1:
jmp SYNERR
.endif
.ifdef CONFIG_2; GO TO
LC721:
cmp #TOKEN_GO-$80
bne SYNERR1
jsr CHRGET
lda #TOKEN_TO
jsr SYNCHR
jmp GOTO
.endif
; ----------------------------------------------------------------------------
; "RESTORE" STATEMENT
; ----------------------------------------------------------------------------
RESTORE:
sec
lda TXTTAB
sbc #$01
ldy TXTTAB+1
bcs SETDA
dey
SETDA:
sta DATPTR
sty DATPTR+1
RET2:
rts
.include "iscntc.s"
;!!! runs into "STOP"
; ----------------------------------------------------------------------------
; "STOP" STATEMENT
; ----------------------------------------------------------------------------
STOP:
bcs END2
; ----------------------------------------------------------------------------
; "END" STATEMENT
; ----------------------------------------------------------------------------
END:
clc
END2:
bne RET1
lda TXTPTR
ldy TXTPTR+1
.if .def(CONFIG_NO_INPUTBUFFER_ZP) && .def(CONFIG_2)
; BUG on AppleSoft I
; fix exists on AppleSoft II
; TXTPTR+1 will always be > 0
ldx CURLIN+1
inx
.endif
beq END4
sta OLDTEXT
sty OLDTEXT+1
CONTROL_C_TYPED:
lda CURLIN
ldy CURLIN+1
sta OLDLIN
sty OLDLIN+1
END4:
pla
pla
L2701:
lda #<QT_BREAK
ldy #>QT_BREAK
.if .def(KBD)
ldx #$00
stx Z14
.endif
bcc L270E
jmp PRINT_ERROR_LINNUM
L270E:
jmp RESTART
.if .def(KBD)
LE664:
tay
jmp SNGFLT
.endif
; ----------------------------------------------------------------------------
; "CONT" COMMAND
; ----------------------------------------------------------------------------
CONT:
bne RET1
ldx #ERR_CANTCONT
ldy OLDTEXT+1
bne L271C
jmp ERROR
L271C:
lda OLDTEXT
sta TXTPTR
sty TXTPTR+1
lda OLDLIN
ldy OLDLIN+1
sta CURLIN
sty CURLIN+1
RET1:
rts
.if .def(KBD)
PRT:
jsr GETBYT
txa
; not ROR bug safe
ror a
ror a
ror a
sta $8F
rts
LE68C:
ldy #$12
LE68E:
lda LEA30,y
sta $03A2,y
dey
bpl LE68E
rts
.endif
.ifndef AIM65
.if .def(CONFIG_NULL) || .def(CONFIG_PRINTNULLS)
; CBM1 has the keyword removed,
; but the code is still here
NULL:
jsr GETBYT
bne RET1
inx
cpx #NULL_MAX
bcs L2739
dex
stx Z15
L2738:
rts
L2739:
jmp IQERR
.endif
.ifndef CONFIG_11A
CLEAR:
bne RET1
jmp CLEARC
.endif
.endif