chris/open-roms
1
0 Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Update FCOMP

Browse Source
This commit is contained in:
Rikard Nordgren authored and FeralChild64 committed 2026-03-29 21:45:24 +02:00
1 parent 94f8dfc822
commit 27b03948a2
6 files changed
+75 -97
Download Patch File Download Diff File Expand all files Collapse all files

No files matched your search

STATUS.md
+1 -1
View File
@@ -239,7 +239,7 @@ Floating point mathematical routines - not official, but well known and broadly
| `$BC3C` | `convert_A_to_FAC1` | DONE | From the Microsoft BASIC, original name: FLOAT |
| `$BC44` | `convert_i16_to_FAC1` | DONE | From the Microsoft BASIC, original name: FLOATS |
| `$BC58` | `abs_FAC1` | DONE | From the Microsoft BASIC, original name: ABS |
| `$BC5B` | `FCOMP` | DONE | |
| `$BC5B` | `FCOMP` | DONE | From the Microsoft BASIC, original name: FCOMP |
| `$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 |
src/aliases/,aliases_ram_lowmem.s
+2 -1
View File
@@ -31,7 +31,8 @@
!addr TEMPPT = $16 ; pointer to the first available slot in the temporary string descriptor stack
!addr LASTPT = $17 ; $17-$18 pointer to the last used slot in the temporary string descriptor
!addr TEMPST = $19 ; $19-$21 temporary string stack descriptors
!addr INDEX = $22 ; $22-$25 temporary variables, [!] our usage might be different
!addr INDEX = $22 ; $22-$23 INDEX1 vector
!addr INDEX2 = $24 ; $24-$25 INDEX2 vector
!addr RESHO = $26 ; $26-$2A temporary variables, [!] our usage might be different
!addr TXTTAB = $2B ; $2B-$2C start of BASIC code
!addr VARTAB = $2D ; $2D-$2E end of BASIC code, start of variables
src/basic/math/FCOMP.s
-84
View File
@@ -1,84 +0,0 @@
;; #LAYOUT# STD * #TAKE
;; #LAYOUT# X16 BASIC_0 #TAKE-OFFSET 2000
;; #LAYOUT# * BASIC_0 #TAKE
;; #LAYOUT# * * #IGNORE
;
; Math package - compare FAC1 with RAM location
;
; Input:
; - .A - address low byte
; - .Y - address high byte
;
; Output:
; - .A - $00 for equal, $01 for FAC1 > RAM, $FF for FAC1 < RAM
; - flags N/Z, Z=1 if equal, N=1 if FAC1 < RAM, Z=0, N=0 if FAC1 > RAM
;
; Notes:
; - uses vector at $24, leaves FAC1 and FAC2 unchanged (Codebase64)
;
; See also:
; - [CM64] Computes Mapping the Commodore 64 - page 115
; - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
; - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
;
FCOMP:
sta INDEX+2
sty INDEX+3
ldy #$01
lda (INDEX+2),Y
eor FAC1_sign ; Check if signs are different
bmi FCOMP_greater_than ; FAC < or > RAM, will be swapped to correct
dey
lda (INDEX+2),Y ; Exponent of RAM float into A
cmp FAC1_exponent
bcc FCOMP_greater_than ; FAC1 > RAM
bne FCOMP_less_than
cmp #$00
beq FCOMP_equal ; FAC1 = RAM = 0
iny
lda (INDEX+2),Y
ora #$80 ; Set highest bit of mantissa (0.5)
cmp FAC1_mantissa
bcc FCOMP_greater_than
bne FCOMP_less_than
iny
lda (INDEX+2),Y
cmp FAC1_mantissa+1
bcc FCOMP_greater_than
bne FCOMP_less_than
iny
lda (INDEX+2),Y
cmp FAC1_mantissa+2
bcc FCOMP_greater_than
bne FCOMP_less_than
iny
lda (INDEX+2),Y
cmp FAC1_mantissa+3
bcc FCOMP_greater_than
bne FCOMP_less_than
FCOMP_equal:
lda #$00
rts
FCOMP_less_than:
lda FAC1_sign
bpl FCOMP_FF
FCOMP_01:
lda #$01
rts
FCOMP_greater_than:
lda FAC1_sign
bpl FCOMP_01
FCOMP_FF:
lda #$FF
rts
src/basic/math/bc5b.FCOMP.jmp.s
-8
View File
@@ -1,8 +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
jmp FCOMP
src/basic/math/bc5b.FCOMP.s
+70
View File
@@ -0,0 +1,70 @@
;; #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 - compare FAC1 with RAM location
;
; Input:
; - .A - address low byte
; - .Y - address high byte
;
; Output:
; - .A - $00 for equal, $01 for FAC1 > RAM, $FF for FAC1 < RAM
; - flags N/Z, Z=1 if equal, N=1 if FAC1 < RAM, Z=0, N=0 if FAC1 > RAM
;
; This is verified to be identical to the original Microsoft implementation where it was named FCOMP.
;
; Notes:
; - uses vector at $24, leaves FAC1 and FAC2 unchanged (Codebase64)
;
; Alternative entry point: FCOMPN - Instead of A set INDEX2 to low byte of address
;
; See also:
; - [CM64] Computes Mapping the Commodore 64 - page 115
; - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
; - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
;
FCOMP:
sta INDEX2+0
FCOMPN:
sty INDEX2+1
ldy #0
lda (INDEX2),Y
iny
tax
beq sgn_FAC1_A ; arg is zero so sign of FAC1 will decide
lda (INDEX2),Y
eor FAC1_sign
bmi sgn_FAC1_A_nozero ; signs differ so sign of FAC will decide
cpx FAC1_exponent
bne @1
lda (INDEX2),Y
ora #$80
cmp FAC1_mantissa+0
bne @1
iny
lda (INDEX2),Y
cmp FAC1_mantissa+1
bne @1
iny
lda (INDEX2),Y
cmp FAC1_mantissa+2
bne @1
iny
lda #$7F
cmp FACOV
lda (INDEX2),Y
sbc FAC1_mantissa+3 ; Get zero if equal
beq QINT_ret
@1:
lda FAC1_sign
bcc @2
eor #$FF
@2:
jmp sgn_A
tools/similarity.c
+2 -3
View File
@@ -20,7 +20,7 @@ int matches[MAX_SIZE];
int phase_mask[MAX_SIZE+MAX_SIZE];
#define NUM_CHUNKS 7
#define NUM_CHUNKS 6
// Pairs of start, end memory addresses of known exact similarity with the open source Microsoft BASIC
unsigned short microsoft_basic_chunks[NUM_CHUNKS * 2] = {
0xB849, 0xB84F,
@@ -28,8 +28,7 @@ unsigned short microsoft_basic_chunks[NUM_CHUNKS * 2] = {
0xB947, 0xB97D,
0xB983, 0xB9BB,
0xBBA2, 0xBC1A,
0xBC2B, 0xBC5A,
0xBC9B, 0xBCF2,
0xBC2B, 0xBCF2,
};