Add FIN

src/basic/,stubs_math/bcf3.FIN.s

@@ -1,25 +0,0 @@
-;; #LAYOUT# STD *       #TAKE
-;; #LAYOUT# X16 BASIC_0 #TAKE-OFFSET 2000
-;; #LAYOUT# *   BASIC_0 #TAKE
-;; #LAYOUT# *   *       #IGNORE
-
-;
-; Math package - imports string to FAC1, ignores spaces
-;
-;
-; Input:
-; - .A needs to be loaded with first char of the string
-; - Carry flag must be clear
-; - string address in $7A/$7B
-;
-; See also:
-; - [CM64] Computes Mapping the Commodore 64 - page 116
-; - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
-; - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
-;
-
-; XXX provide implementation
-
-FIN:
-
-	+STUB_IMPLEMENTATION

src/basic/math/FIN.s

@@ -0,0 +1,155 @@
+;; #LAYOUT# STD *       #TAKE
+;; #LAYOUT# X16 BASIC_0 #TAKE-OFFSET 2000
+;; #LAYOUT# *   BASIC_0 #TAKE
+;; #LAYOUT# *   *       #IGNORE
+
+;
+; Math package - imports string to FAC1, ignores spaces
+;
+;
+; Input:
+; - .A needs to be loaded with first char of the string
+; - Carry flag must be clear
+; - string address in $7A/$7B
+;
+; See also:
+; - [CM64] Computes Mapping the Commodore 64 - page 116
+; - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
+; - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
+;
+
+!ifdef CONFIG_MEMORY_MODEL_38K {
+; NOTE: Currently CHRGET is only available for the 38K model and the equivalent function
+;       does not test for digits to set carry
+
+FIN_NUMDEC      = TEMPF2
+FIN_DIGIT       = TEMPF2 + 1
+FIN_DECFOUND    = TEMPF2 + 2
+FIN_EXPSIGN     = TEMPF2 + 3
+FIN_EXP         = TEMPF2 + 4
+
+
+FIN:
+    ldx #$00
+    stx SGNFLG          ; Sign is positive
+    stx FIN_DECFOUND    ; Decimal point not found
+    stx FIN_EXP         ; Exponent
+    stx FAC1_exponent   ; FAC1 <- 0
+    bcc FIN_loop        ; Starting with digit
+    cmp #$2D            ; Is minus?
+    bne @1
+    dec SGNFLG
+    bne FIN_next        ; Will always branch
+
+@1: cmp #$2B            ; Is plus?
+    beq FIN_next
+
+FIN_loop:
+    bcs FIN_nonnumeric
+    sec
+    sbc #48             ; Convert to number
+    sta FIN_DIGIT
+    jsr mul10_FAC1
+    jsr mov_FAC1_FAC2
+    lda FIN_DIGIT
+    jsr convert_A_to_FAC1
+    jsr add_FAC2_FAC1
+
+    lda FIN_DECFOUND    ; Have we passed the decimal sign?
+    bpl FIN_next
+    inc FIN_NUMDEC
+
+FIN_next:
+    jsr CHRGET
+    +bra FIN_loop
+
+FIN_nonnumeric:
+    cmp #$2E            ; decimal point
+    beq FIN_decimal
+    cmp #$45            ; E
+    beq FIN_exponent
+FIN_finalize:
+    lda FIN_EXP
+    sec
+    sbc FIN_NUMDEC
+    sta FIN_EXP
+    bmi FIN_div_loop
+
+FIN_mul_loop:
+    dec FIN_EXP
+    bmi FIN_out
+    jsr mul10_FAC1
+    +bra FIN_mul_loop
+
+FIN_div_loop:
+    jsr div10_FAC1_p
+    inc FIN_EXP
+    bne FIN_div_loop
+
+FIN_out:
+    lda SGNFLG
+    sta FAC1_sign
+    rts
+    
+FIN_decimal:
+    lda FIN_DECFOUND
+    bmi FIN_finalize
+    dec FIN_DECFOUND    ; Indicate found decimal point
+    sta FIN_NUMDEC      ; Number of decimal places = 0
+    +bra FIN_next
+    
+FIN_exponent:
+    ldx #0
+    stx FIN_EXPSIGN
+    jsr CHRGET
+    bcc FIN_exp_loop
+    cmp #$2D            ; Is minus?
+    bne @1
+    dec FIN_EXPSIGN
+    bne FIN_exp_next    ; Always branches
+@1: cmp #$2B            ; Is plus?
+    beq FIN_exp_next
+    bne FIN_done_exp
+
+FIN_exp_loop:
+     tax
+     lda FIN_EXP
+     cmp #10
+     bcs FIN_exp_limit
+     asl                ; Multiply by 10
+     sta FIN_EXP
+     asl
+     asl
+     clc
+     adc FIN_EXP
+     sta FIN_EXP
+     txa
+     sec
+     sbc #48             ; Convert to number
+     clc
+     adc FIN_EXP
+     sta FIN_EXP
+
+FIN_exp_next:
+     jsr CHRGET
+     bcc FIN_exp_loop
+
+FIN_done_exp:
+     lda FIN_EXP
+     bpl FIN_finalize
+     eor #$FF
+     tax
+     inx
+     stx FIN_EXP
+     +bra FIN_finalize
+
+FIN_exp_limit:
+     ldx FIN_EXPSIGN
+     bmi FIN_zero
+     jmp do_OVERFLOW_error
+
+FIN_zero:
+     ldx #0
+     stx FAC1_exponent
+     rts
+ }

src/basic/math/bcf3.FIN.jmp.s

@@ -0,0 +1,12 @@
+;; #LAYOUT# STD *       #TAKE
+;; #LAYOUT# X16 BASIC_0 #TAKE-OFFSET 2000
+;; #LAYOUT# *   BASIC_0 #TAKE
+;; #LAYOUT# *   *       #IGNORE
+
+; Just a compatibility jump - our routine is longer than original one
+
+!ifdef CONFIG_MEMORY_MODEL_38K {
+    jmp FIN
+} else {
+    +STUB_IMPLEMENTATION
+}