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3 changed files with 140 additions and 212 deletions
334
mandel.s
334
mandel.s
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@ -1,16 +1,16 @@
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; Our zero-page vars
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ox = $80 ; fixed6.26: center point x
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oy = $84 ; fixed6.26: center point y
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cx = $88 ; fixed6.26: c_x
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cy = $8c ; fixed6.26: c_y
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ox = $80 ; fixed8.24: center point x
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oy = $84 ; fixed8.24: center point y
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cx = $88 ; fixed8.24: c_x
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cy = $8c ; fixed8.24: c_y
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zx = $90 ; fixed6.26: z_x
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zy = $94 ; fixed6.26: z_y
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zx_2 = $98 ; fixed6.26: z_x^2
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zy_2 = $9c ; fixed6.26: z_y^2
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zx = $90 ; fixed8.24: z_x
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zy = $94 ; fixed8.24: z_y
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zx_2 = $98 ; fixed8.24: z_x^2
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zy_2 = $9c ; fixed8.24: z_y^2
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zx_zy = $a0 ; fixed6.26: z_x * z_y
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dist = $a4 ; fixed6.26: z_x^2 + z_y^2
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zx_zy = $a0 ; fixed8.24: z_x * z_y
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dist = $a4 ; fixed8.24: z_x^2 + z_y^2
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sx = $a8 ; i16: screen pixel x
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sy = $aa ; i16: screen pixel y
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z_buffer_active = $ac ; boolean: 1 if we triggered the lake, 0 if not
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@ -31,10 +31,10 @@ chroma_offset = $bb ; u8
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palette_ticks = $bc ; u8
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chroma_ticks = $bd ; u8
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count_frames = $be ; u8
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; free space $bf
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count_pixels = $bf ; u8
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count_iters = $c0 ; u16
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; free space c2-cb
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total_pixels = $c0 ; float48
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total_ms = $c6 ; float48
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temp = $cc ; u16
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temp2 = $ce ; u16
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@ -59,12 +59,10 @@ LBUFF = $0580 ; result buffer for FASC routine
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; FP ROM routine vectors
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FASC = $D8E6 ; FLOATING POINT TO ASCII (output in INBUFF, last char has high bit set)
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IFP = $D9AA ; INTEGER TO FLOATING POINT CONVERSION (FR0:u16 -> FR0:float48)
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FPI = $D9D2 ; floating point to integer
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FADD = $DA66 ; ADDITION (FR0 += FR1)
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FSUB = $DA60 ; SUBTRACTION (FR0 -= FR1)
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FMUL = $DADB ; MULTIPLICATION (FR0 *= FR1)
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FDIV = $DB28 ; DIVISION (FR0 /= FR1)
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ZFR0 = $DA44 ; clear FR0
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ZF1 = $DA46 ; CLEAR ZERO PAGE FLOATING POINT NUMBER (XX)
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FLD0R = $DD89 ; LOAD FR0 WITH FLOATING POINT NUMBER (YYXX)
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FLD1R = $DD98 ; LOAD FR1 WITH FLOATING POINT NUMBER (YYXX)
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@ -143,7 +141,7 @@ str_self:
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.byte "MANDEL-6502"
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str_self_end:
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str_speed:
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.byte "us/iter: "
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.byte " ms/px"
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str_speed_end:
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str_run:
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.byte " RUN"
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@ -191,38 +189,20 @@ aspect:
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;
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; 184h is the equiv of 220.8h at square pixels
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; 320 / 220.8 = 1.45 display aspect ratio
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aspect_x: ; fixed3.13 5/4
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.word 5 << (13 - 2)
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aspect_x: ; fixed4.16 5/4
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.word 5 << (12 - 2)
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aspect_y: ; fixed3.13 3/4
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.word 3 << (13 - 2)
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aspect_y: ; fixed4.16 3/4
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.word 3 << (12 - 2)
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sec_per_frame: ; float48 00 . 01 66 66 66 67
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.byte 63 ; exponent/sign - -1 bytes
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.byte $01 ; BCD digits
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ms_per_frame: ; float48 16.66666667
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.byte 64 ; exponent/sign
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.byte $16 ; BCD digits
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.byte $66
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.byte $66
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.byte $66
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.byte $67
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us_per_sec: ; float48 1e9 01 00 0,0 00 . 00
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.byte 67 ; exponent/sign +3 bytes
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.byte $01 ; BCD digits
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.byte $00
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.byte $00
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.byte $00
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.byte $00
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total_iters: ; float48
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.repeat 6
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.byte 0
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.endrepeat
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total_sec: ; float48
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.repeat 6
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.byte 0
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.endrepeat
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display_list_start:
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; 24 lines overscan
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.repeat 3
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@ -254,9 +234,9 @@ display_list_len = display_list_end - display_list_start
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color_map:
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.byte 0
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.repeat 85
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.byte %01010101
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.byte %10101010
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.byte %11111111
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.byte 1
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.byte 2
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.byte 3
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.endrepeat
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@ -305,34 +285,23 @@ fill_masks:
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.byte %00000001
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.byte %00000000
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pixel_masks:
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.byte %11111111
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.byte %11110000
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.byte %11000000
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viewport_zoom:
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.byte 0
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.byte 5
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.byte 7
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.byte 5
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.byte 7
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.byte 7
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.byte 1
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.byte 6
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.byte 8
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.byte 6
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viewport_ox:
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.dword ($00000000 & $3fffffff) << 2
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.dword ($ff110000 & $3fffffff) << 2
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.dword ($ff110000 & $3fffffff) << 2
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.dword ($fe400000 & $3fffffff) << 2
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.dword ($fe3b0000 & $3fffffff) << 2
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.dword $fd220000
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.dword $00000000
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.dword $ff110000
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.dword $ff110000
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.dword $fe400000
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viewport_oy:
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.dword ($00000000 & $3fffffff) << 2
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.dword ($ffb60000 & $3fffffff) << 2
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.dword ($ffbe0000 & $3fffffff) << 2
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.dword ($00000000 & $3fffffff) << 2
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.dword ($fffe0000 & $3fffffff) << 2
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.dword $ff000000
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.dword $00000000
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.dword $ffb60000
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.dword $ffbe0000
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.dword $00000000
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; 2 + 9 * byte cycles
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.macro add bytes, dest, arg1, arg2
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@ -484,6 +453,20 @@ viewport_oy:
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sta dest + 1
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.endmacro
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; input: arg as u8
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; input/output: dest as u16
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; clobbers a, x
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.macro sqr8_add16 dest, arg
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ldx arg
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clc
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lda sqr_lobyte,x
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adc dest
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sta dest
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lda sqr_hibyte,x
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adc dest + 1
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sta dest + 1
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.endmacro
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.segment "TABLES"
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; lookup table for top byte -> PORTB value for bank-switch
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.align 256
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@ -766,8 +749,9 @@ inner_loop:
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; h1*h2*256*256 + h1*l2*256 + h2*l1*256 + l1*l2
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imul8 result, arg1, arg2, xe
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imul8 result + 2, arg1 + 1, arg2 + 1, xe
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lda #0
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sta result + 2
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sta result + 3
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imul8 inter, arg1 + 1, arg2, xe
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add16 result + 1, result + 1, inter
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@ -777,6 +761,9 @@ inner_loop:
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add16 result + 1, result + 1, inter
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add_carry result + 3
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imul8 inter, arg1 + 1, arg2 + 1, xe
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add16 result + 2, result + 2, inter
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; In case of negative inputs, adjust high word
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; https://stackoverflow.com/a/28827013
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lda arg1 + 1
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@ -809,8 +796,9 @@ arg2_pos:
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; h*h*256*256 + h*l*256 + h*l*256 + l*l
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sqr8 result, arg
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sqr8 result + 2, arg + 1
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lda #0
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sta result + 2
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sta result + 3
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imul8 inter, arg + 1, arg, xe
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add16 result + 1, result + 1, inter
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@ -818,6 +806,8 @@ arg2_pos:
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add16 result + 1, result + 1, inter
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add_carry result + 3
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sqr8_add16 result + 2, arg + 1
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rts ; 6 cyc
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.endscope
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.endmacro
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@ -885,8 +875,8 @@ next:
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.proc mandelbrot
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; input:
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; cx: position scaled to 6.26 fixed point - -32..+31.9
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; cy: position scaled to 6.26
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; cx: position scaled to 8.24 fixed point - -128..+127.9
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; cy: position scaled to 8.24
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;
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; output:
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; iter: iteration count at escape or 0
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@ -937,11 +927,6 @@ next:
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sta z_buffer_end
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loop:
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inc count_iters
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bne low_iters
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inc count_iters + 1
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low_iters:
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; iter++ & max-iters break
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inc iter
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bne keep_going
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@ -949,7 +934,7 @@ low_iters:
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keep_going:
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.macro quick_exit arg, max
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; arg: fixed6.26
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; arg: fixed8.24
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; max: integer
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.local positive
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.local negative
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@ -962,12 +947,12 @@ keep_going:
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bmi negative
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positive:
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cmp #(max << 2)
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cmp #max
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bmi all_done ; 'less than'
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jmp exit_path
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negative:
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cmp #(256 - (max << 2))
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cmp #(256 - max)
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beq first_equal ; 'equal' on first byte
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bpl all_done ; 'greater than'
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@ -987,7 +972,7 @@ keep_going:
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all_done:
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.endmacro
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; 6.26: (-32 .. 31.9)
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; 8.24: (-128 .. 127.9)
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; zx = zx_2 - zy_2 + cx
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sub32 zx, zx_2, zy_2
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add32 zx, zx, cx
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@ -998,9 +983,9 @@ keep_going:
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add32 zy, zy, cy
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quick_exit zy, 2
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; convert 6.26 -> 3.13: (-4 .. +3.9)
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shift_round_16 zx, 3
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shift_round_16 zy, 3
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; convert 8.24 -> 4.12: (-8 .. +7.9)
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shift_round_16 zx, 4
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shift_round_16 zy, 4
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; zx_2 = zx * zx
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sqr16 zx_2, zx + 2
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@ -1122,9 +1107,9 @@ enough:
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.endmacro
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.macro zoom_factor dest, src, aspect
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; output: dest: fixed6.26
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; input: src: fixed3.13
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; aspect: fixed3.13
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; output: dest: fixed8.24
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; input: src: fixed4.12
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; aspect: fixed4.12
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; clobbers A, X, flags, etc
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copy16 dest, src
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scale_zoom dest
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@ -1142,11 +1127,8 @@ enough:
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; iter -> color
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ldx iter
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lda color_map,x
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ldx fill_level
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and pixel_masks,x
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sta pixel_color
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lda pixel_masks,x
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eor #$ff
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lda #(255 - 3)
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sta pixel_mask
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; sy -> line base address in temp
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@ -1195,23 +1177,22 @@ point:
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; pixel_mask <<= pixel_shift (shifting in ones)
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and #3
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sta pixel_shift
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lda #3
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sec
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sbc pixel_shift
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tax
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shift_loop:
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beq shift_done
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lsr pixel_color
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lsr pixel_color
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asl pixel_color
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asl pixel_color
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sec
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ror pixel_mask
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rol pixel_mask
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sec
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ror pixel_mask
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rol pixel_mask
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dex
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jmp shift_loop
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shift_done:
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ldy fill_level
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ldx fill_masks,y
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inx
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; pixel_offset = temp >> 2
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lda temp
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lsr a
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@ -1219,25 +1200,12 @@ shift_done:
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sta pixel_offset
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tay
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draw_pixel:
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; read, mask, or, write
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lda (pixel_ptr),y
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and pixel_mask
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ora pixel_color
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sta (pixel_ptr),y
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dex
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beq done
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clc
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lda #40
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adc pixel_ptr
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sta pixel_ptr
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lda #0
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adc pixel_ptr + 1
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sta pixel_ptr + 1
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jmp draw_pixel
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done:
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rts
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.endproc
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@ -1245,7 +1213,6 @@ done:
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; clobbers A, X
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.local loop
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.local done
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.local padding
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ldx #0
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loop:
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cpx #len
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@ -1253,27 +1220,11 @@ loop:
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txa
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tay
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lda (strptr),y
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pha ; save the char for terminator check
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and #$7f ; strip the high bit (terminator)
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tay
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lda char_map,y
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sta textbuffer + col,x
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inx
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pla
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bmi padding
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jmp loop
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padding:
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ldy #32 ; space
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lda char_map,y
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cpx #len
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beq done
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sta textbuffer + col,x
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inx
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jmp padding
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done:
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.endmacro
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@ -1416,7 +1367,7 @@ skip_char:
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plus:
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lda zoom
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cmp #7
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cmp #8
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bpl skip_char
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inc zoom
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jmp done
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@ -1448,10 +1399,6 @@ number_keys:
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beq three
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cpy #KEY_4
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beq four
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cpy #KEY_5
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beq five
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cpy #KEY_6
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beq six
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jmp skip_char
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one:
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@ -1465,12 +1412,6 @@ three:
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jmp load_key_viewport
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four:
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ldx #3
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jmp load_key_viewport
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five:
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ldx #4
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jmp load_key_viewport
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six:
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ldx #5
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; fall through
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load_key_viewport:
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jsr load_viewport
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@ -1601,20 +1542,16 @@ copy_byte_loop:
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|||
jsr SETVBV
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main_loop:
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; count_frames = 0; count_iters = 0
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; count_frames = 0; count_pixels = 0
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lda #0
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sta count_frames
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sta count_iters
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sta count_iters + 1
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sta count_pixels
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; total_sec = 0.0; total_iters = 0.0
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jsr ZFR0
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ldx #.lobyte(total_sec)
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ldy #.hibyte(total_sec)
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jsr FST0R
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ldx #.lobyte(total_iters)
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ldy #.hibyte(total_iters)
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jsr FST0R
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; total_ms = 0.0; total_pixels = 0.0
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ldx #total_ms
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jsr ZF1
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ldx #total_pixels
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||||
jsr ZF1
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||||
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jsr clear_screen
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||||
jsr status_bar
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||||
|
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@ -1686,32 +1623,38 @@ not_skipped_mask:
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|||
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||||
no_key:
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||||
; check if we should update the counters
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||||
;
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||||
; count_pixels >= width? update!
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||||
inc count_pixels
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||||
lda count_pixels
|
||||
cmp #width
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||||
bmi update_status
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||||
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||||
; count_frames >= 120? update!
|
||||
lda count_frames
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||||
cmp #120 ; >= 2 seconds
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||||
bpl update_status
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||||
jmp skipped
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||||
bmi skipped
|
||||
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||||
update_status:
|
||||
; FR0 = (float)count_iters & clear count_iters
|
||||
copy16 FR0, count_iters
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||||
jsr IFP
|
||||
; FR0 = (float)count_pixels & clear count_pixels
|
||||
lda count_pixels
|
||||
sta FR0
|
||||
lda #0
|
||||
sta count_iters
|
||||
sta count_iters + 1
|
||||
sta FR0 + 1
|
||||
sta count_pixels
|
||||
jsr IFP
|
||||
|
||||
; FR1 = total_iters
|
||||
ldx #.lobyte(total_iters)
|
||||
ldy #.hibyte(total_iters)
|
||||
; FR1 = total_pixels
|
||||
ldx #.lobyte(total_pixels)
|
||||
ldy #.hibyte(total_pixels)
|
||||
jsr FLD1R
|
||||
|
||||
; FR0 += FR1
|
||||
jsr FADD
|
||||
|
||||
; total_iters = FR0
|
||||
ldx #.lobyte(total_iters)
|
||||
ldy #.hibyte(total_iters)
|
||||
; total_pixels = FR0
|
||||
ldx #.lobyte(total_pixels)
|
||||
ldy #.hibyte(total_pixels)
|
||||
jsr FST0R
|
||||
|
||||
|
||||
|
|
@ -1724,58 +1667,44 @@ update_status:
|
|||
sta count_frames
|
||||
jsr IFP
|
||||
|
||||
; FR0 *= sec_per_frame
|
||||
ldx #.lobyte(sec_per_frame)
|
||||
ldy #.hibyte(sec_per_frame)
|
||||
; FR0 *= ms_per_frame
|
||||
ldx #.lobyte(ms_per_frame)
|
||||
ldy #.hibyte(ms_per_frame)
|
||||
jsr FLD1R
|
||||
jsr FMUL
|
||||
|
||||
; FR0 += total_sec
|
||||
ldx #.lobyte(total_sec)
|
||||
ldy #.hibyte(total_sec)
|
||||
; FR0 += total_ms
|
||||
ldx #total_ms
|
||||
ldy #0
|
||||
jsr FLD1R
|
||||
jsr FADD
|
||||
|
||||
; total_sec = FR0
|
||||
ldx #.lobyte(total_sec)
|
||||
ldy #.hibyte(total_sec)
|
||||
; total_ms = FR0
|
||||
ldx #total_ms
|
||||
ldy #0
|
||||
jsr FST0R
|
||||
|
||||
; FR0 /= total_iters
|
||||
ldx #.lobyte(total_iters)
|
||||
ldy #.hibyte(total_iters)
|
||||
; FR0 /= total_pixels
|
||||
ldx #total_pixels
|
||||
ldy #0
|
||||
jsr FLD1R
|
||||
jsr FDIV
|
||||
|
||||
; FR0 *= us_per_sec
|
||||
ldx #.lobyte(us_per_sec)
|
||||
ldy #.hibyte(us_per_sec)
|
||||
jsr FLD1R
|
||||
jsr FMUL
|
||||
|
||||
; round (down) to integer
|
||||
jsr FPI
|
||||
clc
|
||||
jsr IFP
|
||||
|
||||
; convert to ASCII in INBUFF
|
||||
jsr FASC
|
||||
|
||||
; print the first 6 digits
|
||||
draw_text speed_start, str_speed_len, str_speed
|
||||
draw_text_indirect speed_start + str_speed_len, speed_precision, INBUFF
|
||||
draw_text_indirect speed_start, speed_precision, INBUFF
|
||||
draw_text speed_start + speed_precision, str_speed_len, str_speed
|
||||
|
||||
skipped:
|
||||
|
||||
; sx += fill_level[fill_masks] + 1
|
||||
ldx fill_level
|
||||
lda fill_masks,x
|
||||
clc
|
||||
adc #1 ; will never carry
|
||||
adc sx
|
||||
lda sx
|
||||
adc #1
|
||||
sta sx
|
||||
lda #0
|
||||
adc sx + 1
|
||||
lda sx + 1
|
||||
adc #0
|
||||
sta sx + 1
|
||||
|
||||
lda sx
|
||||
|
|
@ -1785,15 +1714,12 @@ skipped:
|
|||
|
||||
loop_sx_done:
|
||||
|
||||
; sy += fill_level[fill_masks] + 1
|
||||
ldx fill_level
|
||||
lda fill_masks,x
|
||||
clc
|
||||
adc #1 ; will never carry
|
||||
adc sy
|
||||
lda sy
|
||||
adc #1
|
||||
sta sy
|
||||
lda #0
|
||||
adc sy + 1
|
||||
lda sy + 1
|
||||
adc #0
|
||||
sta sy + 1
|
||||
|
||||
lda sy
|
||||
|
|
|
|||
|
|
@ -18,7 +18,7 @@ Enjoy! I'll probably work on this off and on for the next few weeks until I've g
|
|||
|
||||
## Current state
|
||||
|
||||
Basic rendering is functional, with interactive zoom/pan (+/-/arrows) and 6 preset viewports via the number keys.
|
||||
Basic rendering is functional, with interactive zoom/pan (+/-/arrows) and 4 preset viewports via the number keys.
|
||||
|
||||
The 16-bit signed integer multiplication takes two 16-bit inputs and emits one 32-bit output in the zero page, using the Atari OS ROM's floating point registers as workspaces. Inputs are clobbered.
|
||||
|
||||
|
|
@ -27,7 +27,7 @@ The 16-bit signed integer multiplication takes two 16-bit inputs and emits one 3
|
|||
* when expanded RAM is available as on 130XE, a 64KB 8-bit multiplication table accelerates the remaining multiplications
|
||||
* without expanded RAM, a table of half-squares is used to implement the algorithm from https://everything2.com/title/Fast+6502+multiplication
|
||||
|
||||
The mandelbrot calculations are done using 3.13-precision fixed point numbers with 6.26-precision intermediates.
|
||||
The mandelbrot calculations are done using 4.12-precision fixed point numbers with 8.24-precision intermediates. It may be possible to squish this down to 3.13/6.26.
|
||||
|
||||
Iterations are capped at 255.
|
||||
|
||||
|
|
|
|||
14
todo.md
14
todo.md
|
|
@ -1,17 +1,19 @@
|
|||
things to try:
|
||||
|
||||
* fix status bar to show elapsed time, per-iter time, per-pixel iter count
|
||||
|
||||
* 'turbo' mode disabling graphics in full or part
|
||||
* skip add on the top-byte multiply in sqr8/mul8
|
||||
* should save a few cycles, suggestion by jamey
|
||||
|
||||
* patch the entire expanded-ram imul8xe on top of imul8 to avoid the 3-cycle thunk penalty :D
|
||||
|
||||
* maybe clean up the load/layout of the big mul table
|
||||
|
||||
* consider alternate lookup tables in the top 16KB under ROM
|
||||
* try 3.13 fixed point instead of 4.12 for more precision
|
||||
* can we get away without the extra bit?
|
||||
* since exit compare space would be 6.26 i think so
|
||||
|
||||
* y-axis mirror optimization
|
||||
|
||||
* 'wide pixels' 2x and 4x for a fuller initial image in the tiered rendering
|
||||
* maybe redo tiering to just 4x4, 2x2, 1x1?
|
||||
|
||||
* extract viewport for display & re-input via keyboard
|
||||
|
||||
* fujinet screenshot/viewport uploader
|
||||
|
|
|
|||
Loading…
Reference in a new issue