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Add FOUT

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Rikard Nordgren authored and FeralChild64 committed 2026-04-12 13:13:18 +02:00
1 parent abd67c40f9
commit e3dfe9e0e2
6 files changed
+224 -26
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STATUS.md
+1 -1
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@@ -250,7 +250,7 @@ Floating point mathematical routines - not official, but well known and broadly
| `$BCE9` | `clear_FAC1` | DONE | From the Microsoft BASIC, original name: CLRFAC |
| `$BCF3` | `FIN` | PARTIAL | Only for 38k memory model + not fully tested yet |
| `$BD7E` | `FINLOG` | DONE | From the Microsoft BASIC, original name: FINLOG |
| `$BDDD` | `FOUT` | NOT DONE | outputs FAC1 to string at $0100 |
| `$BDDD` | `FOUT` | DONE | From the Microsoft BASIC, original name: FOUT |
| `$BF71` | `sqr_FAC1` | PARTIAL | needs `sqr_FAC2` |
| `$BF74` | `sqr_FAC2` | NOT DONE | |
| `$BF78` | `pwr_FAC2_MEM` | PARTIAL | needs `pwr_FAC2_FAC1` |
src/aliases/,aliases_ram_lowmem.s
+5 -1
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@@ -49,6 +49,7 @@
!addr INPPTR = $43 ; $43-$44 -- NOT IMPLEMENTED --
!addr VARNAM = $45 ; $45-$46 current variable name
!addr VARPNT = $47 ; $47-$48 current variable/descriptor pointer
!addr FDECPT = VARPNT
!addr FORPNT = $49 ; $49-$4A -- NOT IMPLEMENTED --
!addr OPPTR = $4B ; $4B-$4C helper variable for expression computation, [!] our usage details are different
!addr OPMASK = $4D ; -- NOT IMPLEMENTED --
@@ -59,7 +60,8 @@
!addr OLDOV = $56 ; old floating point overflow byte
!addr TEMPF1 = $57 ; $57-$5B BASIC numeric work area
!addr TEMPF2 = $5C ; $5C-$60 BASIC numeric work area
!addr DECCNT = $5D ; Number of digits after decimal point
!addr TENEXP = $5E ; Exponent count
!addr __FAC1 = $61 ; $61-$66 floating point accumulator 1
!addr FAC1_exponent = $61
!addr FAC1_mantissa = $62 ; $62 - $65
@@ -163,6 +165,8 @@
; Page 1
;
!addr FBUFFR = $100 ; FOUT string buffer
!addr STACK = $100 ; $100-$1FF, processor stack
;
src/basic/,stubs_math/bddd.FOUT.s
-23
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@@ -1,23 +0,0 @@
;; #LAYOUT# STD * #TAKE
;; #LAYOUT# X16 BASIC_0 #TAKE-OFFSET 2000
;; #LAYOUT# * BASIC_0 #TAKE
;; #LAYOUT# * * #IGNORE
;
; Math package - outputs FAC1 to string at $0100
;
; Output:
; - .A - address low byte
; - .Y - address high byte
;
; 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
FOUT:
+STUB_IMPLEMENTATION
src/basic/math/bddd.FOUT.s
+217
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@@ -0,0 +1,217 @@
;; #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 - outputs FAC1 to string at $0100
;
; This is verified to be identical to the original Microsoft implementation where it was named FOUT
;
; Output:
; - .A - address low byte
; - .Y - address high byte
;
; 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
;
FOUT:
ldy #1
FOUTC:
lda #' ' ; Print space if positive.
bit FAC1_sign
bpl FOUT1
lda #$2D
FOUT1: ; FIXME FBUFFR is $0100 13 bytes fstring buffer
sta FBUFFR-1,Y ; STore the character.
sta FAC1_sign ; Make FAC1 pos for QINT
sty FBUFPT ; Save for later
iny
lda #'0' ; Get zero to type if FAC1=0
ldx FAC1_exponent
bne @1
jmp FOUT19
@1 lda #0
cpx #$80 ; Is number .LT. 1.0 ?
beq FOUT37 ; No
bcs FOUT7
FOUT37:
lda #<const_NZMIL
ldy #>const_NZMIL
jsr mul_MEM_FAC1
lda #$F7
FOUT7:
sta DECCNT ; Save count or zero it
FOUT4:
lda #<const_NZ9999
ldy #>const_NZ9999
jsr FCOMP ; Is number .GT. 999999.499 ? or 999999999.499?
beq BIGGES
bpl FOUT9 ; Yes. Make it smaller
FOUT3:
lda #<const_NZ0999
ldy #>const_NZ0999
jsr FCOMP ; Is number .GT. 99999.9499 ? or 99999999.9499?
beq FOUT38
bpl FOUT5 ; Yes. Done multiplying
FOUT38:
jsr MUL10 ; Make it bigger
dec DECCNT
bne FOUT3 ; See if that does it.
FOUT9:
jsr div10_FAC1_p ; Make it smaller
inc DECCNT
bne FOUT4 ; See if that does it
FOUT5:
jsr add_HALF_FAC1 ; Add a half to round up
BIGGES:
jsr QINT
ldx #1 ; Decimal point count
lda DECCNT
clc
adc #$0A ; Should the number be printed in E notation? i.e. is number .LT. .01 ?
bmi FOUTPI ; Yes
cmp #$0B ; Is it .GT. 999999 (999999999)?
bcs FOUT6 ; Yes. Use E notation.
adc #$FF ; Number of places before decimal point
tax
lda #2 ; No E notation
FOUTPI:
sec
FOUT6:
sbc #2 ; Effectively add 5 to orig exp
sta TENEXP ; That is the exponent to print
stx DECCNT ; Number of decimal places
txa
beq FOUT39
bpl FOUT8 ; Some places before dec pnt
FOUT39:
ldy FBUFPT ; Get pointer to output
lda #'.' ; Put in "."
iny
sta FBUFFR-1,Y
txa
beq FOUT16
lda #'0' ; Get the ensuing zero
iny
sta FBUFFR-1,Y
FOUT16:
sty FBUFPT ; Save for later.
FOUT8:
ldy #0
FOUTIM:
ldx #$80 ; First pass thru, X has MSB set
FOUT2:
lda FAC1_mantissa+3
clc
adc FOUTBL+3,Y
sta FAC1_mantissa+3
lda FAC1_mantissa+2
adc FOUTBL+2,Y
sta FAC1_mantissa+2
lda FAC1_mantissa+1
adc FOUTBL+1,Y
sta FAC1_mantissa+1
lda FAC1_mantissa+0
adc FOUTBL,Y
sta FAC1_mantissa+0
inx ; It was done yet another time
bcs FOUT41
bpl FOUT2
bmi FOUT40
FOUT41:
bmi FOUT2
FOUT40:
txa
bcc FOUTYP ; Can use A as is
eor #$FF ; Find 11.-[A]
adc #10 ; CF C is still on to complete negation. And will always be on after
FOUTYP:
adc #'0' - 1 ; Get a character to print
iny ; Bum pointer up
iny
iny
iny
sty FDECPT
ldy FBUFPT
iny ; Point to place to store output
tax
and #$7F ; Get rid of MSB
sta FBUFFR-1,Y
dec DECCNT
bne STXBUF ; Not time for DP yet
lda #'.' ; "."
iny
sta FBUFFR-1,Y ; Store DP
STXBUF:
sty FBUFPT ; Store PNTR for later
ldy FDECPT
FOUTCM:
txa ; Complement X
eor #$FF ; Complement A
and #$80 ; Save only MSB
tax
cpy #FDCEND-FOUTBL
beq FOULDY
cpy #TIMEND-FOUTBL
bne FOUT2 ; Continue with output
FOULDY:
ldy FBUFPT ; Get back output PNTR
FOUT11:
lda FBUFFR-1,Y ; Remove trailing zeroes
dey
cmp #'0'
beq FOUT11
cmp #'.'
beq FOUT12 ; Run into DP STOP
iny ; Something else. Save it
FOUT12:
lda #'+'
ldx TENEXP
beq FOUT17 ; No exponent to output
bpl FOUT14
lda #0
sec
sbc TENEXP
tax
lda #'-' ; Exponent is negative
FOUT14:
sta FBUFFR+1,Y ; Store sign of exp
lda #'E'
sta FBUFFR,Y ; Store the "E" character
txa
ldx #'0' - 1
sec
FOUT15:
inx ; Move closer to output value
sbc #10
bcs FOUT15 ; Not negative yet
adc #'0' + 10 ; Get second output character
sta FBUFFR+3,Y ; Store high digit
txa
sta FBUFFR+2,Y ; Store low digit
lda #0 ; Put in terminator
sta FBUFFR+4,Y
beq FOUT20 ; Return (always branches)
FOUT19:
sta FBUFFR-1,Y ; Store the character
FOUT17:
lda #0 ; A terminator
sta FBUFFR,Y
FOUT20:
lda #<FBUFFR
ldy #>FBUFFR
FPWRRT:
rts ; All done
src/basic/,stubs_math/bddd.interop → src/basic/math/bddd.interop
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File renamed without changes.
tools/similarity.c
+1 -1
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@@ -30,7 +30,7 @@ unsigned short microsoft_basic_chunks[NUM_CHUNKS * 2] = {
0xBA28, 0xBCF2,
0xBD7E, 0xBD90,
0xBDB3, 0xBDC1,
0xBF11, 0xBF51,
0xBDDD, 0xBF51,
0xBFB4, 0xBFBE,
};