Add build for the original C64

Had to deactivate it for MEGA65 because of conflicting code also placed at e000

Makefile

@@ -136,6 +136,7 @@ GEN_ZMAC_H     = $(DIR_ZMAC_TMP)/doc.inl
 
 # List of build directories
 
+DIR_C64        = build/target_c64
 DIR_CUS        = build/target_custom
 DIR_GEN        = build/target_generic
 DIR_GENCRT     = build/target_generic_crt
@@ -149,6 +150,7 @@ DIR_X16        = build/target_cx16
 # List of config files
 
 CFG_CUS        = src/,,config_custom.s 
+CFG_C64        = src/,,config_c64.s
 CFG_GEN        = src/,,config_generic.s
 CFG_GENCRT     = src/,,config_generic_crt.s
 CFG_TST38      = src/,,config_testing_38K.s
@@ -161,6 +163,7 @@ CFG_U64CRT     = src/,,config_ultimate64_crt.s
 # List of files with generated strings
 
 GEN_STR_CUS    = $(DIR_CUS)/,generated/,packed_strings.s
+GEN_STR_C64    = $(DIR_C64)/,generated/,packed_strings.s
 GEN_STR_GEN    = $(DIR_GEN)/,generated/,packed_strings.s
 GEN_STR_GENCRT = $(DIR_GENCRT)/,generated/,packed_strings.s
 GEN_STR_TST38  = $(DIR_TST38)/,generated/,packed_strings.s
@@ -208,6 +211,7 @@ TARGET_CHR_ORF     = build/chargen_openroms.rom
 TARGET_CHR_PXL     = build/chargen_pxlfont.rom
 
 TARGET_CUS_B       = build/basic_custom.rom
+TARGET_C64_B       = build/basic_c64.rom
 TARGET_GEN_B       = build/basic_generic.rom
 TARGET_GENCRT_B    = build/basic_generic_crt.rom
 TARGET_TST38_B     = build/basic_testing_38K.rom
@@ -216,6 +220,7 @@ TARGET_U64_B       = build/basic_ultimate64.rom
 TARGET_U64CRT_B    = build/basic_ultimate64_crt.rom
 
 TARGET_CUS_K       = build/kernal_custom.rom
+TARGET_C64_K       = build/kernal_c64.rom
 TARGET_GEN_K       = build/kernal_generic.rom
 TARGET_GENCRT_K    = build/kernal_generic_crt.rom
 TARGET_TST38_K     = build/kernal_testing_38K.rom
@@ -231,6 +236,7 @@ TARGET_M65_x_PXL   = build/mega65.rom
 TARGET_X16_x       = build/cx16-dummy.rom
 
 TARGET_LIST_CUS    = $(TARGET_CUS_B) $(TARGET_CUS_K)
+TARGET_LIST_C64    = $(TARGET_C64_B) $(TARGET_C64_K)
 TARGET_LIST_GEN    = $(TARGET_GEN_B) $(TARGET_GEN_K)
 TARGET_LIST_GENCRT = $(TARGET_GENCRT_B) $(TARGET_GENCRT_K) $(TARGET_GENCRT_X)
 TARGET_LIST_TST38  = $(TARGET_TST38_B) $(TARGET_TST38_K)
@@ -242,6 +248,7 @@ TARGET_Z80TEST     = ./build/cpm/Z80TEST.COM
 
 TARGET_LIST        = $(TARGET_CHR_ORF)     \
                      $(TARGET_LIST_CUS)    \
+                     $(TARGET_LIST_C64)    \
                      $(TARGET_LIST_GEN)    \
                      $(TARGET_LIST_GENCRT) \
                      $(TARGET_LIST_TST38)  \
@@ -376,6 +383,8 @@ build/patched_chargen/pxlfont.pcg: $(TOOL_PATCH_CHARGEN) $(TARGET_CHR_PXL)
 
 $(DIR_CUS)/OUTB_x.BIN $(DIR_CUS)/BASIC_combined.vs: \
     $(TOOL_ASSEMBLER) $(TOOL_BUILD_SEGMENT) $(DEP_BASIC) $(CFG_CUS) $(GEN_STR_CUS) $(DIR_CUS)/KERNAL_combined.sym
+$(DIR_C64)/OUTB_x.BIN $(DIR_C64)/BASIC_combined.vs: \
+    $(TOOL_ASSEMBLER) $(TOOL_BUILD_SEGMENT) $(DEP_BASIC) $(CFG_C64) $(GEN_STR_C64) $(DIR_C64)/KERNAL_combined.sym
 $(DIR_GEN)/OUTB_x.BIN $(DIR_GEN)/BASIC_combined.vs: \
     $(TOOL_ASSEMBLER) $(TOOL_BUILD_SEGMENT) $(DEP_BASIC) $(CFG_GEN) $(GEN_STR_GEN) $(DIR_GEN)/KERNAL_combined.sym
 $(DIR_TST38)/OUTB_x.BIN $(DIR_TST38)/BASIC_combined.vs: \
@@ -387,6 +396,8 @@ $(DIR_U64)/OUTB_x.BIN $(DIR_U64)/BASIC_combined.vs: \
 
 $(DIR_CUS)/OUTK_x.BIN $(DIR_CUS)/KERNAL_combined.vs $(DIR_CUS)/KERNAL_combined.sym: \
     $(TOOL_ASSEMBLER) $(TOOL_BUILD_SEGMENT) $(DEP_KERNAL) $(CFG_CUS) $(GEN_STR_CUS)
+$(DIR_C64)/OUTK_x.BIN $(DIR_C64)/KERNAL_combined.vs $(DIR_C64)/KERNAL_combined.sym: \
+    $(TOOL_ASSEMBLER) $(TOOL_BUILD_SEGMENT) $(DEP_KERNAL) $(CFG_C64) $(GEN_STR_C64)
 $(DIR_GEN)/OUTK_x.BIN $(DIR_GEN)/KERNAL_combined.vs $(DIR_GEN)/KERNAL_combined.sym: \
     $(TOOL_ASSEMBLER) $(TOOL_BUILD_SEGMENT) $(DEP_KERNAL) $(CFG_GEN) $(GEN_STR_GEN)
 $(DIR_TST38)/OUTK_x.BIN $(DIR_TST38)/KERNAL_combined.vs $(DIR_TST38)/KERNAL_combined.sym: \
@@ -445,6 +456,7 @@ $(DIR_X16)/kernal.seg_1 $(DIR_X16)/KERNAL_1_combined.vs $(DIR_X16)/KERNAL_1_comb
     $(TOOL_ASSEMBLER) $(TOOL_BUILD_SEGMENT) $(DEP_KERNAL) $(CFG_X16) $(GEN_STR_X16) $(DIR_X16)/KERNAL_0_combined.sym
 
 $(DIR_CUS)/OUTx_x.BIN:     $(DIR_CUS)/OUTB_x.BIN     $(DIR_CUS)/OUTK_x.BIN
+$(DIR_C64)/OUTx_x.BIN:     $(DIR_C64)/OUTB_x.BIN     $(DIR_C64)/OUTK_x.BIN
 $(DIR_GEN)/OUTx_x.BIN:     $(DIR_GEN)/OUTB_x.BIN     $(DIR_GEN)/OUTK_x.BIN
 $(DIR_GENCRT)/OUTx_0.BIN:  $(DIR_GENCRT)/OUTB_0.BIN  $(DIR_GENCRT)/OUTK_0.BIN
 $(DIR_TST38)/OUTx_x.BIN:   $(DIR_TST38)/OUTB_x.BIN   $(DIR_TST38)/OUTK_x.BIN
@@ -455,18 +467,21 @@ $(DIR_U64CRT)/OUTx_0.BIN:  $(DIR_U64CRT)/OUTB_0.BIN  $(DIR_U64CRT)/OUTK_0.BIN
 $(DIR_X16)/OUTx_0.BIN:     $(DIR_X16)/OUTB_0.BIN     $(DIR_X16)/OUTK_0.BIN
 
 $(TARGET_CUS_B):    $(DIR_CUS)/OUTx_x.BIN
+$(TARGET_C64_B):    $(DIR_C64)/OUTx_x.BIN
 $(TARGET_GEN_B):    $(DIR_GEN)/OUTx_x.BIN
 $(TARGET_TST38_B):  $(DIR_TST38)/OUTx_x.BIN
 $(TARGET_TST60_B):  $(DIR_TST60)/OUTx_x.BIN
 $(TARGET_U64_B):    $(DIR_U64)/OUTx_x.BIN
 
 $(TARGET_CUS_K):    $(DIR_CUS)/OUTx_x.BIN
+$(TARGET_C64_K):    $(DIR_C64)/OUTx_x.BIN
 $(TARGET_GEN_K):    $(DIR_GEN)/OUTx_x.BIN
 $(TARGET_TST38_K):  $(DIR_TST38)/OUTx_x.BIN
 $(TARGET_TST60_K):  $(DIR_TST60)/OUTx_x.BIN
 $(TARGET_U64_K):    $(DIR_U64)/OUTx_x.BIN
 
 build/symbols_custom.vs:          $(DIR_CUS)/BASIC_combined.vs       $(DIR_CUS)/KERNAL_combined.vs
+build/symbols_c64.vs:             $(DIR_C64)/BASIC_combined.vs       $(DIR_C64)/KERNAL_combined.vs
 build/symbols_generic.vs:         $(DIR_GEN)/BASIC_combined.vs       $(DIR_GEN)/KERNAL_combined.vs
 build/symbols_generic_crt.vs:     $(DIR_GENCRT)/BASIC_0_combined.vs  $(DIR_GENCRT)/KERNAL_0_combined.vs
 build/symbols_testing_38K.vs:     $(DIR_TST38)/BASIC_combined.vs     $(DIR_TST38)/KERNAL_combined.vs
@@ -480,6 +495,10 @@ $(GEN_STR_CUS): $(TOOL_GENERATE_STRINGS) $(CFG_CUS)
 	@mkdir -p $(DIR_CUS)/,generated
 	$(TOOL_GENERATE_STRINGS) -o $@ -c $(CFG_CUS)
 
+$(GEN_STR_C64): $(TOOL_GENERATE_STRINGS) $(CFG_C64)
+	@mkdir -p $(DIR_C64)/,generated
+	$(TOOL_GENERATE_STRINGS) -o $@ -c $(CFG_C64)
+
 $(GEN_STR_GEN): $(TOOL_GENERATE_STRINGS) $(CFG_GEN)
 	@mkdir -p $(DIR_GEN)/,generated
 	$(TOOL_GENERATE_STRINGS) -o $@ -c $(CFG_GEN)
@@ -521,6 +540,7 @@ build/,generated/,z80_tables.s: $(TOOL_GENERATE_Z80_TABLES)
 	$(TOOL_GENERATE_Z80_TABLES) -o build/,generated/,z80_tables.s
 
 GEN_STR_custom         = $(GEN_STR_CUS)
+GEN_STR_c64            = $(GEN_STR_C64)
 GEN_STR_generic        = $(GEN_STR_GEN)
 GEN_STR_generic_crt    = $(GEN_STR_GENCRT)
 GEN_STR_testing_38K    = $(GEN_STR_TST38)

STATUS.md

@@ -248,15 +248,15 @@ Floating point mathematical routines - not official, but well known and broadly
 | `$BC9B`   | `QINT`                 | DONE     | From the Microsoft BASIC, original name: QINT      |
 | `$BCCC`   | `int_FAC1`             | DONE     | From the Microsoft BASIC, original name: INT       |
 | `$BCE9`   | `clear_FAC1`           | DONE     | From the Microsoft BASIC, original name: CLRFAC    |
-| `$BCF3`   | `FIN`                  | PARTIAL  | Only for 38k memory model + not fully tested yet   |
+| `$BCF3`   | `FIN`                  | PARTIAL  | From the Microsoft BASIC Only for 38k memory model |
 | `$BD7E`   | `FINLOG`               | DONE     | From the Microsoft BASIC, original name: FINLOG    |
 | `$BDDD`   | `FOUT`                 | DONE     | From the Microsoft BASIC, original name: FOUT      |
 | `$BF71`   | `sqr_FAC1`             | DONE     | From the Microsoft BASIC, original name: SQR       |
 | `$BF74`   | `sqr_FAC2`             | DONE     | From the Microsoft BASIC, no label                 |
 | `$BF78`   | `pwr_FAC2_MEM`         | DONE     | From the Microsoft BASIC, no label                 |
-| `$BF7B`   | `pwr_FAC2_FAC1`        | NOT DONE |                                                    |
+| `$BF7B`   | `pwr_FAC2_FAC1`        | DONE     | From the Microsoft BASIC, original name: FPWRT     |
 | `$BFB4`   | `toggle_sign_FAC1`     | DONE     | From the Microsoft BASIC, original name: NEGOP     |
-| `$BFED`   | `exp_FAC1`             | NOT DONE |                                                    |
+| `$BFED`   | `exp_FAC1`             | PARTIAL  | From the Microsoft BASIC Only for the 38k model    |
 | `$E043`   | `poly1_FAC1`           | DONE     | From the Microsoft BASIC, original name: POLYX     |
 | `$E059`   | `poly2_FAC1`           | DONE     | From the Microsoft BASIC, original name: POLY      |
 | `$E097`   | `rnd_FAC1`             | DONE     |                                                    |

src/,,config_c64.s

@@ -0,0 +1,129 @@
+
+;; #CONFIG# ID $64 ; should be 1 byte, different for each config file!
+
+;
+; Please read CONFIG.md before modifying this file!
+;
+
+; Idea:
+; Maximum compatibility with the original C64
+; Original Microsoft BASIC with bugs and all
+; No customizations of the KERNAL
+
+
+
+; --- Hardware platform and brand
+
+;; #CONFIG# PLATFORM_COMMODORE_64      YES
+;; #CONFIG# BRAND_CUSTOM               "C64"
+
+
+; --- Processor instruction set
+
+;; #CONFIG# CPU_MOS_6502               YES
+;; #CONFIG# CPU_DTV_6502               NO
+;; #CONFIG# CPU_RCW_65C02              NO
+;; #CONFIG# CPU_WDC_65C02              NO
+;; #CONFIG# CPU_WDC_65816              NO
+;; #CONFIG# CPU_CSG_65CE02             NO
+
+
+; --- Memory model
+
+;; #CONFIG# MEMORY_MODEL_38K           YES
+;; #CONFIG# MEMORY_MODEL_46K           NO
+;; #CONFIG# MEMORY_MODEL_50K           NO
+;; #CONFIG# MEMORY_MODEL_60K           NO
+
+
+; --- IEC bus configuration
+
+;; #CONFIG# IEC                        YES
+;; #CONFIG# IEC_DOLPHINDOS             NO
+;; #CONFIG# IEC_DOLPHINDOS_FAST        NO
+;; #CONFIG# IEC_JIFFYDOS               NO
+;; #CONFIG# IEC_JIFFYDOS_BLANK         NO
+
+
+; --- Tape deck configuration
+
+;; #CONFIG# TAPE_NORMAL                YES
+;; #CONFIG# TAPE_TURBO                 NO
+;; #CONFIG# TAPE_AUTODETECT            NO
+;; #CONFIG# TAPE_NO_KEY_SENSE          NO
+;; #CONFIG# TAPE_NO_MOTOR_CONTROL      NO
+
+
+; --- Sound support
+
+;; #CONFIG# SID_2ND_ADDRESS            NO
+;; #CONFIG# SID_3RD_ADDRESS            NO
+;; #CONFIG# SID_D4XX                   NO
+;; #CONFIG# SID_D5XX                   NO
+;; #CONFIG# SID_D6XX                   NO
+;; #CONFIG# SID_D7XX                   NO
+
+
+; --- Keyboard settings
+
+;; #CONFIG# KEYBOARD_C128              NO
+;; #CONFIG# KEYBOARD_C128_CAPS_LOCK    NO
+;; #CONFIG# KEY_REPEAT_DEFAULT         NO
+;; #CONFIG# KEY_REPEAT_ALWAYS          NO
+;; #CONFIG# KEY_FAST_SCAN              YES
+;; #CONFIG# JOY1_CURSOR                YES
+;; #CONFIG# JOY2_CURSOR                YES
+
+;; #CONFIG# PROGRAMMABLE_KEYS          YES
+
+;; #CONFIG# KEYCMD_RUN                 "\5FL"
+
+;; #CONFIG# KEYCMD_F1                  "@8$"
+;; #CONFIG# KEYCMD_F2                  "LOAD"
+;; #CONFIG# KEYCMD_F3                  "@9$"
+;; #CONFIG# KEYCMD_F4                  "RUN:"
+;; #CONFIG# KEYCMD_F5                  "@10$"
+;; #CONFIG# KEYCMD_F6                  NO
+;; #CONFIG# KEYCMD_F7                  "@11$"
+;; #CONFIG# KEYCMD_F8                  NO
+
+;; #CONFIG# KEYCMD_HELP                "LIST"
+
+
+; --- Screen editor
+
+;; #CONFIG# EDIT_STOPQUOTE             YES
+
+
+; --- Software features
+
+;; #CONFIG# PANIC_SCREEN               YES
+;; #CONFIG# DOS_WEDGE                  NO
+;; #CONFIG# TAPE_WEDGE                 NO
+;; #CONFIG# TAPE_HEAD_ALIGN            NO
+;; #CONFIG# BCD_SAFE_INTERRUPTS        YES
+
+
+; --- BASIC features
+
+;; #CONFIG# ORIGINAL_UNPATCHED_BASIC   YES
+;; #CONFIG# TRANSCENDENTAL_FUNCTIONS   YES
+
+
+; --- Eye candy
+
+;; #CONFIG# COLORS_BRAND               NO
+;; #CONFIG# BANNER_SIMPLE              YES
+;; #CONFIG# BANNER_FANCY               NO
+;; #CONFIG# SHOW_FEATURES              YES
+
+
+; --- Debug options
+
+;; #CONFIG# DBG_STUBS_BRK              NO
+;; #CONFIG# DBG_PRINTF                 NO
+
+
+; --- Other
+
+;; #CONFIG# COMPRESSION_LVL_2          NO

src/aliases/,aliases_ram_lowmem.s

@@ -15,6 +15,7 @@
 	!addr ADRAY1    = $03 ; $03-$04
 	!addr ADRAY2    = $05 ; $05-$06
 	!addr CHARAC    = $07 ;          [!] our implementation might be different  XXX give more details
+	!addr INTEGR    = CHARAC
 	!addr ENDCHR    = $08 ;          [!] our implementation might be different  XXX give more details
 	!addr TRMPOS    = $09 ;          -- NOT IMPLEMENTED -- [!] on MEGA65 also used by DOS Wedge under MONITOR
 	!addr VERCKB    = $0A ;          flag used by BASIC, 0 - LOAD, 1 - VERIFY, [!] on MEGA65 also used by DOS Wedge
@@ -63,6 +64,8 @@
 	!addr TEMPF2    = $5C ; $5C-$60  BASIC numeric work area
     !addr DECCNT    = $5D ; Number of digits after decimal point
     !addr TENEXP    = $5E ; Exponent count
+    !addr DPTFLG    = $5F ; Decimal point flag for FIN
+    !addr EXPSGN    = $60 ; Exponent sign for FIN
 	!addr __FAC1    = $61 ; $61-$66  floating point accumulator 1
 	!addr FAC1_exponent   = $61
 	!addr FAC1_mantissa   = $62 ; $62 - $65

src/basic/,stubs_math/bf7b.pwr_FAC2_FAC1.s

@@ -1,26 +0,0 @@
-;; #LAYOUT# STD *       #TAKE
-;; #LAYOUT# X16 BASIC_0 #TAKE-OFFSET 2000
-;; #LAYOUT# *   BASIC_0 #TAKE
-;; #LAYOUT# *   *       #IGNORE
-
-;
-; Math package - set FAC1 as FAC2 raised to the power of FAC1
-;
-; Input:
-; - .A - must load FAC1 exponent ($61) beforehand to set the zero flag
-;
-; Note:
-; - load FAC2 after FAC1, or mimic the Kernals sign comparison (XXX do we need it?)
-; - uses exp(x*log(y)) formula to calculate y^x; slow and inaccurate
-;
-; See also:
-; - [CM64] Computes Mapping the Commodore 64 - page 117
-; - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
-; - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
-;
-
-; XXX provide implementation
-
-pwr_FAC2_FAC1:
-
-	+STUB_IMPLEMENTATION

src/basic/,stubs_math/bfed.exp_FAC1.s

@@ -1,20 +0,0 @@
-;; #LAYOUT# STD *       #TAKE
-;; #LAYOUT# X16 BASIC_0 #TAKE-OFFSET 2000
-;; #LAYOUT# *   BASIC_0 #TAKE
-;; #LAYOUT# *   *       #IGNORE
-
-;
-; Math package - exponential function, e raised to FAC1 power
-;
-;
-; See also:
-; - [CM64] Computes Mapping the Commodore 64 - page 117
-; - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
-; - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
-;
-
-; XXX provide implementation
-
-exp_FAC1:
-
-	+STUB_IMPLEMENTATION

src/basic/math/FIN.s

@@ -1,152 +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
-;
-
-!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
-    lda FIN_DIGIT
-    jsr FINLOG
-    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

@@ -1,12 +0,0 @@
-;; #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
-}

src/basic/math/bcf3.FIN.s

@@ -0,0 +1,130 @@
+;; #LAYOUT# STD *       #TAKE
+;; #LAYOUT# X16 BASIC_0 #TAKE-OFFSET 2000
+;; #LAYOUT# *   BASIC_0 #TAKE
+;; #LAYOUT# *   *       #IGNORE
+
+; This file is under the MIT license, it contains code released by Microsoft Corporation.
+; See LICENSE for more information.
+
+; Math package - imports string to FAC1, ignores spaces
+;
+; This is verified to be identical to the original Microsoft implementation where it was named FIN.
+;
+; Input:
+; - .A needs to be loaded with first char of the string
+; - Carry flag must be clear
+; - string address in $7A/$7B
+;
+; See also:
+; - [CM64] Computes Mapping the Commodore 64 - page 116
+; - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
+; - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
+;
+
+; NUMBER INPUT IS LEFT IN FAC.
+; AT ENTRY [TXTPTR] POINTS TO THE FIRST CHARACTER IN A TEXT BUFFER.
+; THE FIRST CHARACTER IS ALSO IN ACCA. FIN PACKS THE DIGITS
+; INTO THE FAC AS AN INTEGER AND KEEPS TRACK OF WHERE THE
+; DECIMAL POINT IS. [DPTFLG] TELL WHETHER A DP HAS BEEN
+; SEEN. [DECCNT] IS THE NUMBER OF DIGITS AFTER THE DP.
+; AT THE END [DECCNT] AND THE EXPONENT ARE USED TO
+; DETERMINE HOW MANY TIMES TO MULTIPLY OR DIVIDE BY TEN
+; TO GET THE CORRECT NUMBER.
+
+
+!ifdef CONFIG_MEMORY_MODEL_38K {
+
+FIN:
+        ldy #0          ; Zero FAC1_sign and SGNFLG
+        ldx #10         ; Zero exp and hi bytes
+FINZLP:
+        sty DECCNT,X    ; Zero low bytes
+        dex             ; Zero TENEXP and EXPSGN
+        bpl FINZLP      ; Zero DECCNT, DPTFLG
+        bcc FINDGQ      ; Flags still set from CHRGET
+        cmp #'-'        ; A negative sign?
+        bne QPLUS       ; No, try plus sign
+        stx SGNFLG      ; It's negative
+        beq FINC        ; Always branches
+QPLUS:
+        cmp #'+'        ; Plus sign?
+        bne FIN1        ; Yes, skip it
+FINC:
+        jsr CHRGET
+FINDGQ:
+        bcc FINDIG
+FIN1:
+        cmp #'.'        ; The decimal point?
+        beq FINDP       ; No kidding
+        cmp #'E'        ; Exponent follows
+        bne FINE        ; No
+	    ;HERE TO CHECK FOR SIGN OF EXP.
+        jsr CHRGET      ; Yes, Get another
+        bcc FNEDG1      ; It is a digit. (Easier than backing up pointer)
+        cmp #$AB        ; Minus with sign set (from table)
+        beq FINEC1      ; Negate
+        cmp #'-'        ; Minus sign?
+        beq FINEC1
+        cmp #$AA        ; Plus with sign set (from table)
+        beq FINEC
+        cmp #'+'        ; Plus sign?
+        beq FINEC
+        bne FINEC2
+FINEC1:
+        ror EXPSGN      ; Turn it on
+FINEC:
+        jsr CHRGET      ; Get another
+FNEDG1:
+        bcc FINEDG      ; It is a digit
+FINEC2:
+        bit EXPSGN
+        bpl FINE
+        lda #0
+        sec
+        sbc TENEXP
+        jmp FINE1
+FINDP:
+        ror DPTFLG
+        bit DPTFLG
+        bvc FINC
+FINE:
+        lda TENEXP
+FINE1:
+        sec
+        sbc DECCNT      ; Get number of places to shift
+        sta TENEXP
+        beq FINQNG      ; Negate?
+        bpl FINMUL      ; Positive so multiply
+FINDIV:
+        jsr div10_FAC1_p
+        inc TENEXP      ; Done?
+        bne FINDIV      ; No
+        beq FINQNG      ; Yes
+FINMUL:
+        jsr mul10_FAC1
+        dec TENEXP      ; Done
+        bne FINMUL      ; No
+FINQNG:
+        lda SGNFLG
+        bmi NEGXQS      ; If positive, Return
+        rts
+NEGXQS:
+        jmp toggle_sign_FAC1    ; Otherwise, negate and return
+
+FINDIG:
+        pha
+        bit DPTFLG
+        bpl FINDG1
+        inc DECCNT
+FINDG1:
+        jsr mul10_FAC1
+        pla             ; Get it back
+        sec
+        sbc #'0'
+        jsr FINLOG      ; Add it in
+        jmp FINC
+
+
+} else {
+    +STUB_IMPLEMENTATION
+}

src/basic/math/bd91.FINEDG.s

@@ -0,0 +1,43 @@
+;; #LAYOUT# STD *       #TAKE
+;; #LAYOUT# X16 BASIC_0 #TAKE-OFFSET 2000
+;; #LAYOUT# *   BASIC_0 #TAKE
+;; #LAYOUT# *   *       #IGNORE
+
+; This file is under the MIT license, it contains code released by Microsoft Corporation.
+; See LICENSE for more information.
+
+; Math package - add an ASCII digit in A that has been converted to a signed integer to FAC1
+;
+; This is verified to be identical to the original Microsoft implementation where it was named FINEDG.
+;
+
+; HERE PACK IN THE NEXT DIGIT OF THE EXPONENT.
+; MULTIPLY THE OLD EXP BY 10 AND ADD IN THE NEXT
+; DIGIT. NOTE: EXP OVERFLOW IS NOT CHECKED FOR.
+
+!ifdef CONFIG_MEMORY_MODEL_38K {
+
+FINEDG:
+    lda TENEXP          ; Get exp so far
+    cmp #10             ; Will result be >= 100
+    bcc MLEX10
+    lda #100            ; Get 100
+    bit EXPSGN
+    bmi MLEXMI          ; If neg exp, no check for overflow
+    jmp overflow_error
+MLEX10:
+    asl                 ; Mult by 2 twice
+    asl  
+    clc                 ; Possible shift out of high
+    adc TENEXP          ; Like multiplying by five
+    asl                 ; And now by ten
+    clc
+    ldy #0
+    adc (TXTPTR),Y
+    sec
+    sbc #'0'
+MLEXMI:
+    sta TENEXP          ; Save result
+    jmp FINEC
+    
+}

src/basic/math/div_FAC1_denorm.s

@@ -1,68 +0,0 @@
-;; #LAYOUT# STD *       #TAKE
-;; #LAYOUT# *   BASIC_0 #TAKE
-;; #LAYOUT# *   *       #IGNORE
-
-;
-; Math package - denormalize FAC1 mantissa and adapt its exponent accordingly for division
-;
-
-div_FAC1_denorm:
-
-	; Set FACOV to 0, no need for increased precision here
-
-	lda #$00
-	sta FACOV
-
-	; Start by moving whole bytes, if possible
-
-	lda FAC1_mantissa+3
-	bne div_FAC1_denorm_by_bit         ; branch if last byte of mantissa is non-zero
-
-	lda FAC1_exponent
-	cmp #$08
-	bcc div_FAC1_denorm_by_bit         ; branch if not suitable to increment exponent by 8
-
-	; Increment exponent
-
-	sbc #$08                           ; Carry already sec
-	sta FAC1_exponent
-
-	; Move mantissa bytes
-
-	lda FAC1_mantissa+2
-	sta FAC1_mantissa+3
-	lda FAC1_mantissa+1
-	sta FAC1_mantissa+2	
-	lda FAC1_mantissa+0
-	sta FAC1_mantissa+1
-	lda #$00
-	sta FAC1_mantissa+0
-
-	beq div_FAC1_denorm                ; branch always
-
-div_FAC1_denorm_by_bit:
-
-	lda FAC1_mantissa+3
-	and #$01
-	bne div_FAC1_denorm_done           ; branch if lowest bit of mantissa is already 1
-
-	lda FAC1_exponent
-	beq div_FAC1_denorm_done           ; branch if not suitable to decrement exponent
-
-	; Decrement exponent
-
-	dec FAC1_exponent
-
-	; Move mantissa bits
-
-	clc
-	ror FAC1_mantissa+0
-	ror FAC1_mantissa+1
-	ror FAC1_mantissa+2
-	ror FAC1_mantissa+3
-
-	bcc div_FAC1_denorm_by_bit         ; branch always
-
-div_FAC1_denorm_done:
-
-	rts

src/basic/math/div_mantissas.s

@@ -1,84 +0,0 @@
-;; #LAYOUT# STD *       #TAKE
-;; #LAYOUT# *   BASIC_0 #TAKE
-;; #LAYOUT# *   *       #IGNORE
-
-; Math package - 32-bit mantissa division, based on code by Verz
-;
-; divident: FAC2_mantissa, divisor: FAC1_mantissa (without FACOV), result: FAC2_mantissa, remainder: RESHO
-; temporary storage: INDEX+0, INDEX+1, INDEX+2, INDEX+3
-;
-; RESHO (remainder) should be set to 0 before
-;
-; see https://codebase64.org/doku.php?id=base:24bit_division_24-bit_result
-
-; XXX test this
-
-div_mantissas:
-
-	ldx #32                            ; repeat for each bit
-
-	; FALLTROUGH
-
-div_mantissas_loop:
-
-	; Multiply divident by 2, msb -> Carry
-
-	asl FAC2_mantissa+3
-	rol FAC2_mantissa+2
-	rol FAC2_mantissa+1
-	rol FAC2_mantissa+0
-
-	; Multiply remainder by 2, lsb <- Carry
-
-	rol RESHO+3
-	rol RESHO+2
-	rol RESHO+1
-	rol RESHO+0
-
-	; Subtract divisor from the remainder, result to INDEX and .Y
-
-	sec
-	lda RESHO+3
-	sbc FAC1_mantissa+3
-	sta INDEX+3
-
-	lda RESHO+2
-	sbc FAC1_mantissa+2
-	sta INDEX+2
-
-	lda RESHO+1
-	sbc FAC1_mantissa+1
-	sta INDEX+1
-
-	lda RESHO+0
-	sbc FAC1_mantissa+0
-
-	bcc div_mantissas_skip             ; if Carry is not set then divisor did not fit in remainder yet
-	sta INDEX+0
-
-	; Save subtraction result as new remainder
-
-	lda INDEX+3
-	sta RESHO+3
-
-	lda INDEX+2
-	sta RESHO+2
-
-	lda INDEX+1
-	sta RESHO+1
-
-	lda INDEX+0
-	sta RESHO+0
-
-	; Increment result cause divisor fit in 1 times
-
-	inc FAC2_mantissa+3
-
-	; FALLTROUGH
-
-div_mantissas_skip:
-
-	dex
-	bne div_mantissas_loop
-
-	rts

src/basic/math/mul10_FAC1_mul2.s

@@ -1,16 +0,0 @@
-;; #LAYOUT# STD *       #TAKE
-;; #LAYOUT# *   BASIC_0 #TAKE
-;; #LAYOUT# *   *       #IGNORE
-
-;
-; Multiply FAC1 by 2, do not normalize
-;
-
-mul10_FAC1_mul2:
-
-	; Increment the exponent
-
-	inc FAC1_exponent
-	+beq overflow_error
-
-	rts

src/basic/math/muldiv_RESHO_helpers.s

@@ -1,30 +0,0 @@
-;; #LAYOUT# STD *       #TAKE
-;; #LAYOUT# *   BASIC_0 #TAKE
-;; #LAYOUT# *   *       #IGNORE
-
-;
-; Math package - helper routines for RESHO manipulation
-;
-
-
-muldiv_RESHO_set_0:
-
-	lda #$00
-	sta RESHO+0
-	sta RESHO+1
-	sta RESHO+2
-	sta RESHO+3
-	sta RESHO+4
-
-	rts
-
-
-muldiv_RESHO_01_add_A:
-
-	clc
-	adc RESHO+0
-	sta RESHO+0
-	bcc @1
-	inc RESHO+1
-@1:
-	rts

src/basic/math_consts/b1a5.const_NEG_32768.s

@@ -3,8 +3,13 @@
 ;; #LAYOUT# *   BASIC_0 #TAKE
 ;; #LAYOUT# *   *       #IGNORE
 
+; This file is under the MIT license, it contains code released by Microsoft Corporation.
+; See LICENSE for more information.
+
+; Math package - The floating point constant -32768
+;
+; This is verified to be identical to the original Microsoft implementation where it was named N32768.
 ;
-; Math package - a constant, for documentation see:
 ; - https://www.c64-wiki.com/wiki/BASIC-ROM
 ; - Computes Mapping the Commodore 64, page 105
 ;

src/basic/math_mov/mov_FAC1_MEM.s

@@ -1,74 +0,0 @@
-;; #LAYOUT# STD *       #TAKE
-;; #LAYOUT# *   BASIC_0 #TAKE
-;; #LAYOUT# *   *       #IGNORE
-
-;
-; Math package - copy FAC1 to memory location, do not round
-;
-; Input:
-; - .X - address low byte
-; - .Y - address high byte
-;
-; Output:
-; - .A - FAC1 exponent
-;
-; See also:
-; - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
-; - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
-;
-
-mov_FAC1_MEM:
-
-	; Original routines use $22/$23 location for a vector too, see here:
-	; - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
-
-	sty INDEX+1
-	stx INDEX+0
-
-	ldy #$00
-
-	; Copy exponent
-
-	lda FAC1_exponent
-	sta (INDEX), y
-	beq mov_FAC1_MEM_end               ; for 0 no need to copy anything more
-
-	; Copy first byte of mantissa
-
-	iny
-	lda FAC2_mantissa+3
-	sta (INDEX), y
-
-	; Copy the sign       XXX try to optimize this part
-
-	lda FAC1_sign
-	bne @1
-
-	lda FAC2_mantissa+3
-	and #$7F
-	sta (INDEX), y
-@1:
-	; Copy remaining parts of mantissa
-
-	iny
-	lda FAC2_mantissa+2
-	sta (INDEX), y
-
-	iny
-	lda FAC2_mantissa+1
-	sta (INDEX), y
-
-	iny
-	lda FAC2_mantissa+0
-	sta (INDEX), y
-
-	; Checked, that mov_FAC1_MEM works on real ROM too (at $BBD7),
-	; and clears FACOV in a similar way as mov_FAC1_FAC2 does (not surprising)
-
-	ldy #$00
-	sty FACOV
-
-mov_FAC1_MEM_end:
-
-	lda FAC1_exponent
-	rts

src/basic/math_trans/bf7b.pwr_FAC2_FAC1.s

@@ -0,0 +1,74 @@
+;; #LAYOUT# STD *       #TAKE
+;; #LAYOUT# X16 BASIC_0 #TAKE-OFFSET 2000
+;; #LAYOUT# *   BASIC_0 #TAKE
+;; #LAYOUT# *   *       #IGNORE
+
+; This file is under the MIT license, it contains code released by Microsoft Corporation.
+; See LICENSE for more information.
+
+; Math package - set FAC1 as FAC2 raised to the power of FAC1
+;
+; This is verified to be almost identical to the original Microsoft implementation where it was named FPWRT.
+;
+; Input:
+; - .A - must load FAC1 exponent ($61) beforehand to set the zero flag
+;
+; Note:
+; - load FAC2 after FAC1, or mimic the Kernals sign comparison (XXX do we need it?)
+; - uses exp(x*log(y)) formula to calculate y^x; slow and inaccurate
+;
+; See also:
+; - [CM64] Computes Mapping the Commodore 64 - page 117
+; - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
+; - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
+;
+
+; EXPONENTIATION ---  X^Y.
+; N.B.  0^0=1
+; FIRST CHECK IF Y=0. IF SO, THE RESULT IS 1.
+; NEXT CHECK IF X=0. IF SO THE RESULT IS 0.
+; THEN CHECK IF X.GT.0. IF NOT CHECK THAT Y IS AN INTEGER.
+; IF SO, NEGATE X, SO THAT LOG DOESN'T GIVE FCERR.
+; IF X IS NEGATIVE AND Y IS ODD, NEGATE THE RESULT
+; RETURNED BY EXP.
+; TO COMPUTE THE RESULT USE X^Y=EXP((Y*LOG(X)).
+
+!ifdef CONFIG_TRANSCENDENTAL_FUNCTIONS {
+!ifdef CONFIG_MEMORY_MODEL_38K {
+
+pwr_FAC2_FAC1:
+
+    beq exp_FAC1        ; If FAC1=0, just exponentiate that
+    lda FAC2_exponent   ; Is X=0?
+    bne FPWRT1
+    jmp ZEROF1          ; Zero FAC1
+FPWRT1:
+    ldx #TEMPF3         ; Save for later in a temp
+    ldy #0
+    jsr mov_r_FAC1_MEM
+	; Y=0 already. Good in case no one calls INT
+    lda FAC2_sign
+    bpl FPWR1           ; No problems if X>0
+    jsr int_FAC1        ; Integerize the FAC1
+    lda #TEMPF3         ; Get addr of comperand
+    ldy #0
+    jsr FCOMP           ; Equal?
+    bne FPWR1           ; Leave X neg. log will blow him out. A=-1 and Y is irrelevant
+    tya                 ; Negate X. Make positive
+    ldy INTEGR          ; Get evenness
+FPWR1:
+    jsr mov_FAC2_FAC1_sign      ; Alternate entry point
+    tya
+    pha                 ; Save evenness for later
+    jsr log_FAC1        ; Find log
+    lda #TEMPF3         ; Multiply FAC1 times log(x)
+    ldy #0
+    jsr mul_MEM_FAC1
+    jsr exp_FAC1        ; Exponentiate the FAC1
+    pla
+    lsr                 ; Is it even=
+    bcc NEGRTS          ; Yes. or X>0
+
+    ; FALLTHROUGH to toggle_sign_FAC1
+}
+}

src/basic/math_trans/bfed.exp_FAC1.s

@@ -0,0 +1,47 @@
+;; #LAYOUT# STD *       #TAKE
+;; #LAYOUT# X16 BASIC_0 #TAKE-OFFSET 2000
+;; #LAYOUT# *   BASIC_0 #TAKE
+;; #LAYOUT# *   *       #IGNORE
+
+; This file is under the MIT license, it contains code released by Microsoft Corporation.
+; See LICENSE for more information.
+
+; Math package - exponential function, e raised to FAC1 power
+;
+; This is verified to be almost identical to the original Microsoft implementation where it was named EXP.
+; The addition is the jmp between the two ROMs
+;
+; See also:
+; - [CM64] Computes Mapping the Commodore 64 - page 117
+; - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
+; - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
+;
+
+; FIRST SAVE THE ORIGINAL ARGUMENT AND MULTIPLY THE FAC BY
+; LOG2(E). THE RESULT IS USED TO DETERMINE IF OVERFLOW
+; WILL OCCUR SINCE EXP(X)=2^(X*LOG2(E)) WHERE
+; LOG2(E)=LOG(E) BASE 2. THEN SAVE THE INTEGER PART OF
+; THIS TO SCALE THE ANSWER AT THE END. SINCE
+; 2^Y=2^INT(Y)*2^(Y-INT(Y)) AND 2^INT(Y) IS EASY TO COMPUTE.
+; NOW COMPUTE 2^(X*LOG2(E)-INT(X*LOG2(E)) BY
+; P(LN(2)*(INT(X*LOG2(E))+1)-X) WHERE P IS AN APPROXIMATION
+; POLYNOMIAL. THE RESULT IS THEN SCALED BY THE POWER OF 2
+; PREVIOUSLY SAVED.
+
+!ifdef CONFIG_TRANSCENDENTAL_FUNCTIONS {
+!ifdef CONFIG_MEMORY_MODEL_38K {
+
+exp_FAC1:
+
+        lda #<const_INV_LOG_2       ; Multiply by log_2(e)
+        ldy #>const_INV_LOG_2
+        jsr mul_MEM_FAC1
+        lda FACOV
+        adc #$50
+        bcc @1
+        jsr INCRND
+@1      jmp STOLD                   ; The BASIC ROM ends here so we need to jump to the KERNAL ROM
+       
+ } else {
+    jmp do_NOT_IMPLEMENTED_error
+} }

src/basic/math_trans/e000.exp_FAC1_contd.s

@@ -0,0 +1,53 @@
+;; #LAYOUT# STD *       #TAKE
+;; #LAYOUT# *   BASIC_0 #TAKE
+;; #LAYOUT# *   *       #IGNORE
+
+; This file is under the MIT license, it contains code released by Microsoft Corporation.
+; See LICENSE for more information.
+
+; Continuation of the exp function in the BASIC part of KERNAL ROM
+
+!ifdef CONFIG_TRANSCENDENTAL_FUNCTIONS {
+!ifdef CONFIG_MEMORY_MODEL_38K {
+
+STOLD:
+        sta OLDOV
+        jsr mov_FAC1_FAC2           ; To save in FAC2 without ROUND
+        lda FAC1_exponent
+        cmp #$88                    ; IF abs(FAC1) >= 128, too big
+        bcc @3  
+
+@2
+        jsr MLDVEX                 	; overflow or overflow
+@3
+        jsr int_FAC1
+        lda CHARAC                  ; Get low part
+        clc
+        adc #$81
+        beq @2                      ; overflow or overflow !!
+        sec
+        sbc #1                      ; Subtract 1
+        pha                         ; Save a while
+        ldx #5                      ; Prep to swap FAC1 and FAC2
+@4
+        lda FAC2_exponent,X
+        ldy FAC1_exponent,X
+        sta FAC1_exponent,X
+        sty FAC2_exponent,X
+        dex
+        bpl @4
+        lda OLDOV
+        sta FACOV
+        jsr sub_FAC2_FAC1
+        jsr toggle_sign_FAC1        ; Negate FAC1
+        lda #<poly_exp
+        ldy #>poly_exp
+        jsr poly2_FAC1
+        lda #$00
+        sta ARISGN                  ; Multiply by positive 1.0
+        pla                         ; Get scale factor
+        jsr MLDEXP                  ; Modify FAC1_exponent and check for overflow
+        rts
+        
+ }
+ }

strings/00205BBC

@@ -0,0 +1,3 @@
+JSR $BC5B
+
+Call to known BASIC function FCOMP

strings/20730090

@@ -0,0 +1,3 @@
+JSR $0073 + BCC
+
+Call CHRGET in zero page. From BASIC

strings/20790020F3BC68

@@ -0,0 +1 @@
+Call CHRGOT and FIN. Both known BASIC functions

strings/20D4BBA5

@@ -0,0 +1,3 @@
+JSR $BBD4 + LDA
+
+Call known floating point move function in BASIC

strings/6020A6B3

@@ -0,0 +1,3 @@
+RTS + JSR $B3A6
+
+Call BASIC error function

strings/B490034C

@@ -0,0 +1,3 @@
+$B4 + BCC $03 + JMP
+
+Fragment

tools/similarity.c

@@ -20,21 +20,19 @@ int matches[MAX_SIZE];
 
 int phase_mask[MAX_SIZE+MAX_SIZE];
 
-#define NUM_CHUNKS 14
+#define NUM_CHUNKS 12
 // Pairs of start, end memory addresses of known exact similarity with the open source Microsoft BASIC
 unsigned short microsoft_basic_chunks[NUM_CHUNKS * 2] = {
     0xAEA8, 0xAEAC,
+    0xB1A5, 0xB1A9,
     0xB248, 0xB24C,
     0xB391, 0xB39D,
     0xB3A2, 0xB3A5,
     0xB849, 0xB97D, 
-    0xB983, 0xBCF2,
-    0xBD7E, 0xBD90,
-    0xBDB3, 0xBDC1,
+    0xB983, 0xBDC1,
     0xBDDD, 0xBF51,
-    0xBF71, 0xBF7A,
-    0xBFB4, 0xBFEC,
-    0xE043, 0xE08C,
+    0xBF71, 0xBFFF,
+    0xE000, 0xE08C,
     0xE264, 0xE2C2,     // Two byte gap here is an optimization
     0xE2C5, 0xE37A,
 };
@@ -307,16 +305,18 @@ int main(int argc,char **argv)
 	    fclose(f);
 	  }
 
-	  // Otherwise, the match is unexplained.
-	  matches[k]++;
-	  
-	  // Display particularly long matches
-	  printf("$%04X = $%04X :",i,j);
-	  for(int b=0;b<k;b++) {
-	    printf(" %02X",f1[i+b]);
+      if (k > 3) {
+
+	    // Otherwise, the match is unexplained.
+        matches[k]++;
+
+	    // Display particularly long matches
+	    printf("$%04X = $%04X :",i,j);
+	    for(int b=0;b<k;b++) {
+	      printf(" %02X",f1[i+b]);
+	    }
+	    printf("\n");
 	  }
-	  printf("\n");
-	  
 	}
       }
     }