229 lines
4.3 KiB
ArmAsm
229 lines
4.3 KiB
ArmAsm
; code to use the FAC (floating point accumulator)
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; to generate plasmagoria sine tables
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; 232 bytes = initial implementation
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; 218 bytes = increment high byte of destination instead of loading
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; 208 bytes = modify 1->4 on the fly
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; 205 bytes = make page increment common code
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; 198 bytes = convert thirty-two to twenty-four on fly
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; 188 bytes = convert forty-seven to thirty-eight with one byte
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; 173 bytes = assume constants on same page
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; 171 bytes = optimize save/load of loop index
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; 169 bytes = optimize multiply by 8
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; 166 bytes = separate common sin code
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; 164 bytes = move more to common sin code
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; 162 bytes = move more to common sin code
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qint = $EBF2 ; convert FAC to 32-bit int?
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fadd = $E7BE ; FAC = (Y:A)+FAC
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movmf = $EB2B ; move fac to mem: round FAC and store at Y:X
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fmult = $E97F ; FAC = (Y:A) * FAC
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float = $EB93 ; signed value in A to FAC
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sin = $EFF1
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ARG = $A5 ; A5-AA
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FAC = $9D ; 9D-A2
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; code uses: 5E/5F "index" in load arg from Y:A
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; uses ARG (A5-AA) for argument
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; uses FAC (9D-A2)
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TEMP1 = $FE
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OURX = $FF
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sin1 = $2000
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sin2 = $2100
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sin3 = $2200
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save = $2300
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HGR = $F3E2
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FULLGR = $C052
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add_debut:
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jsr HGR
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bit FULLGR
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;====================================================
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; sin1[i]=round(47.0+
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; 32.0*sin(i*(PI*2.0/256.0))+
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; 16.0*sin(2.0*i*(PI*2.0/256.0)));
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; sin1[i]=round(47.0+
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; 16*(2.0*sin(i*(PI*2.0/256.0))+
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; sin(2.0*i*(PI*2.0/256.0)));
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; already set up for this one
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jsr make_sin_table
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;===================================================
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; sin2[i]=round(47.0+
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; 32.0*sin(4.0*i*(PI*2.0/256.0))+
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; 16.0*sin(3.0*i*(PI*2.0/256.0)));
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; 47 is same, 32 is same, 16 is same
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; convert one to four
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lda #$7d ; only one byte different
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sta one_input
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; load 3 instead of 2 (assume on same page)
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lda #<three_input
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sta sin_table_input3_smc+1
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jsr make_sin_table
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;======================================================
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; sin3[i]=round(38.0+
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; 24.0*sin(3.0*i*(PI*2.0/256.0))+
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; 16.0*sin(8.0*i*(PI*2.0/256.0)));
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; convert 47 to 38
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lda #$18
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sta forty_seven+1
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; convert 32 to 24
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dec thirty_two
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lda #$40
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sta thirty_two+1
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; ideally, convert 4->3
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; load 3 input (assume on same page)
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lda #<three_input
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sta sin_table_input1_smc+1
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; convert four to eight
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inc one_input ; increment power of two
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; load 8 input (assume on same page)
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lda #<one_input
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sta sin_table_input3_smc+1
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jsr make_sin_table
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end:
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jmp end
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;===============================
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;===============================
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;===============================
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;===============================
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;===============================
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make_sin_table:
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ldx #0
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sin_loop:
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stx OURX
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sin_table_input1_smc:
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lda #<one_input
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; thirtytwo or twentyfour
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ldx #<thirty_two
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jsr sin_common
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jsr movmf ; save FAC to mem
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sin_table_input3_smc:
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lda #<two_input
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; always 16
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ldx #<sixteen
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jsr sin_common
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; add first sine
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txa
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jsr fadd ; FAC=FAC+(previous result)
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; add constant 47 or 38
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lda #<forty_seven
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ldy #>forty_seven
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jsr fadd ; FAC=FAC+constant
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jsr qint ; convert to integer
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lda FAC+4 ; get bottom byte
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ldx OURX
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sin_table_dest_smc:
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sta sin1,X ; save to memory
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inx ; move to next
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bne sin_loop ; loop until done
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inc sin_table_dest_smc+2 ; point to next location
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rts
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;==============================
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; sin_common
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;==============================
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; A = low byte for input multiplier
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; X = low byte for result multiplier
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sin_common:
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stx TEMP1
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pha
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lda OURX
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jsr float ; FAC = float(OURX) (again)
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pla
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ldy #>one_input ; high byte, assume always same
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jsr fmult ; FAC=FAC*(constant from RAM)
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jsr sin ; FAC=sin(FAC)
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ldy #>thirty_two ; high byte, assume always same
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lda TEMP1
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jsr fmult ; FAC=constant*FAC
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ldy #>save
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ldx #<save
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rts
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sixteen:
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.byte $85,$00,$00,$00,$00
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;twenty_four:
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; .byte $85,$40,$00,$00,$00
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thirty_two:
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.byte $86,$00,$00,$00,$00
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;thirty_eight:
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; .byte $86,$18,$00,$00,$00
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; 2^5 = 32, 1.0011 0000 = 1/8+1/16
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forty_seven:
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.byte $86,$3C,$00,$00,$00
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; 32 * 1.0111 10000 = 1/4+1/8+1/16+1/32
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one_input:
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; 1*2*pi/256 = .0736310778
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.byte $7b,$49,$0F,$da,$a2
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two_input:
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; 2*2*pi/256 = .0736310778
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.byte $7c,$49,$0F,$da,$a2
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three_input:
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; 3*2*pi/256 = .0736310778
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.byte $7d,$16,$cb,$e3,$f9
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;four_input:
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; ; 4*2*pi/256 = .0736310778
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; .byte $7d,$49,$0F,$da,$a2
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;eight_input:
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; ; 8*2*pi/256 = .196349541
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; .byte $7E,$49,$0F,$da,$a2
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