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No commits in common. "57975b7158c8dae6ee2d10519a4bca36f3b6dac1" and "d36667938d8a3b11ac9c1cb7ecaf80125a1c19ba" have entirely different histories.
57975b7158
...
d36667938d
1 changed files with 87 additions and 66 deletions
153
mandel.s
153
mandel.s
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@ -1,17 +1,17 @@
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; Our zero-page vars
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sx = $80 ; i16: screen pixel x
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sy = $82 ; i16: screen pixel y
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ox = $84 ; fixed4.12: center point x
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oy = $86 ; fixed4.12: center point y
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cx = $84 ; fixed4.12: c_x
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cy = $86 ; fixed4.12: c_y
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zx = $88 ; fixed4.12: z_x
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zy = $8a ; fixed4.12: z_y
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ox = $84 ; fixed3.13: center point x
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oy = $86 ; fixed3.13: center point y
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cx = $84 ; fixed3.13: c_x
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cy = $86 ; fixed3.13: c_y
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zx = $88 ; fixed3.13: z_x
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zy = $8a ; fixed3.13: z_y
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zx_2 = $90 ; fixed8.24: z_x^2
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zy_2 = $94 ; fixed8.24: z_y^2
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zx_zy = $98 ; fixed8.24: z_x * z_y
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dist = $9c ; fixed8.24: z_x^2 + z_y^2
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zx_2 = $90 ; fixed6.26: z_x^2
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zy_2 = $94 ; fixed6.26: z_y^2
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zx_zy = $98 ; fixed6.26: z_x * z_y
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dist = $9c ; fixed6.26: z_x^2 + z_y^2
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iter = $a0 ; u8: iteration count
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zoom = $a1 ; u8: zoom shift level
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@ -42,6 +42,8 @@ half_height = height >> 1
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width = 160
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half_width = width >> 1
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stride = width >> 2
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width_ratio_3_13 = (5 << 11) ; 5/4
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height_ratio_3_13 = (3 << 11) ; 5/4
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DMACTL = $D400
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DLISTL = $D402
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@ -99,12 +101,18 @@ aspect:
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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:
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.word 5 << (12 - 2)
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.word 5 << (13 - 2)
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aspect_y:
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.word 3 << (12 - 2)
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.word 3 << (13 - 2)
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bit_masks:
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.byte 3
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.byte 3 << 2
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.byte 3 << 4
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.byte 3 << 6
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display_list_start:
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; 24 lines overscan
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.repeat 3
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@ -160,7 +168,7 @@ color_map:
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.endmacro
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.macro add32 dest, arg1, arg2
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add 4, dest, arg2, dest
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add 2, dest, arg2, dest
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.endmacro
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; 2 + 9 * byte cycles
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@ -236,6 +244,21 @@ color_map:
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neg 4, arg
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.endmacro
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.macro extend_8_16 dest, src
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; clobbers A, X
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; 13-15 cycles
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.local positive
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.local negative
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ldx #0 ; 2 cyc
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lda src ; 3 cyc
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sta dest ; 3 cyc
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bpl positive ; 2 cyc
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negative:
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dex ; 2 cyc
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positive:
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stx dest + 1 ; 3 cyc
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.endmacro
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; inner loop for imul16
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; bitnum < 8: 25 or 41 cycles
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; bitnum >= 8: 30 or 46 cycles
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@ -254,10 +277,10 @@ color_map:
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; 5 cycles either way
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.if bitnum < 8
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lda arg1 ; 3 cyc
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and #(1 << (bitnum)) ; 2 cyc
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and #(1 << bitnum) ; 2 cyc
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.else
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lda arg1 + 1 ; 3 cyc
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and #(1 << ((bitnum) - 8)) ; 2 cyc
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and #(1 << (bitnum - 8)) ; 2 cyc
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.endif
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bne one ; 2 cyc
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@ -284,6 +307,7 @@ next:
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ror result ; 5 cyc
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.endif
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.endmacro
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; 5 to 25 cycles
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@ -306,18 +330,11 @@ positive:
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copy32 dest, FR2 ; 24 cyc
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.endmacro
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.macro shift_round_16 arg, shift
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.repeat shift
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shl32 arg
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.endrepeat
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round16 arg
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.endmacro
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.macro imul16_round dest, arg1, arg2, shift
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.macro imul16_round dest, arg1, arg2
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copy16 FR0, arg1 ; 12 cyc
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copy16 FR1, arg2 ; 12 cyc
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jsr imul16_func ; 470-780 cyc
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shift_round_16 FR2, shift
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round16 FR2 ; 5-28 cyc
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copy16 dest, FR2 + 2 ; 12 cyc
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.endmacro
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@ -421,60 +438,71 @@ next:
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; dist = 0
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; iter = 0
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lda #00
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ldx #(iter - zx + 1)
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ldx iter - zx
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initloop:
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sta zx - 1,x
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sta zx,x
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dex
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bne initloop
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loop:
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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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; 1939 - 3007 cyc
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; iter++ & max-iters break = 7 cyc
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inc iter ; 5 cyc
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bne keep_going ; 2 cyc
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rts
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keep_going:
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.macro quick_exit arg
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.local keep_going
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lda arg + 1
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cmp #(4 << 4)
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bmi keep_going
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rts
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keep_going:
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.endmacro
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; 4.12: (-8 .. +7.9)
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; zx = zx_2 - zy_2 + cx
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; zx = zx_2 - zy_2 + cx = 3 * 20 = 60 cyc
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sub16 zx, zx_2, zy_2
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add16 zx, zx, cx
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quick_exit zx
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; zy = zx_zy + zx_zy + cy
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add16 zy, zx_zy, zx_zy
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; zy = zx_zy + zx_zy + cy = 3 * 20 = 60 cyc
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sub16 zy, zx_zy, zx_zy
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add16 zy, zy, cy
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; zx_2 = zx * zx
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imul16_round zx_2, zx, zx, 4
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quick_exit dist
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; 8.24: (-128 .. +127.9)
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; zx_2 = zx * zx = 518 - 828 cyc
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imul16 zx_2, zx, zx
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; zy_2 = zy * zy
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imul16_round zy_2, zy, zy, 4
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quick_exit dist
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; zy_2 = zy * zy = 518 - 828 cyc
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imul16 zy_2, zy, zy
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; zx_zy = zx * zy
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imul16_round zx_zy, zx, zy, 4
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quick_exit dist
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; zx_zy = zx * zy = 518 - 828 cyc
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imul16 zx_zy, zx, zy
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; dist = zx_2 + zy_2
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add16 dist, zx_2, zy_2
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quick_exit dist
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; dist = zx_2 + zy_2 = 38 cyc
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add32 dist, zx_2, zy_2
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; if dist >= 4 break, else continue iterating = 7 cyc
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lda dist + 3 ; 3 cyc
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cmp #4 ; 2 cyc
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bmi still_in ; 2 cyc
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rts
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still_in:
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; shift and round zx_2 to 4.12 = (60 + 5) - (60 + 28) = 65 - 88 cyc
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.repeat 4 ; 60 cyc
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shl24 zx_2 ; 15 cyc
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.endrepeat
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round16 zx_2 ; 5-28 cycles
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; shift and round zy_2 to 4.12 = (20 + 5) - (20 + 28) = 65 - 88 cyc
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.repeat 4 ; 60 cyc
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shl24 zy_2 ; 15 cyc
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.endrepeat
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round16 zy_2 ; 5-28 cycles
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; shift and round zx_zy to 4.12 = (20 + 5) - (20 + 28) = 65 - 88 cyc
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.repeat 4 ; 60 cyc
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shl24 zx_zy ; 15 cyc
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.endrepeat
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round16 zx_zy ; 5-28 cycles
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; if may be in the lake, look for looping output with a small buffer
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; as an optimization vs running to max iters
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jmp loop
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peace_out:
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rts
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jmp loop ; 3 cycles
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.endproc
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@ -495,7 +523,7 @@ enough:
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; cy = cy * (3 / 4)
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; cx = cx * (5 / 4)
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imul16_round dest, dest, aspect, 4
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imul16_round dest, dest, aspect
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.endmacro
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.proc pset
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@ -556,9 +584,6 @@ 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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@ -612,13 +637,9 @@ done:
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sta ox + 1
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sta oy
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sta oy + 1
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; zoom = 2x
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lda #1
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sta zoom
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; Disable display DMA
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lda #0
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sta DMACTL
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; zero the range from framebuffer_top to framebuffer_end
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