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Changeset 4f508e6 in buchla-68k for vlib/tsplot4.s
- Timestamp:
- 07/01/2017 02:34:46 PM (7 years ago)
- Branches:
- master
- Children:
- 08e1da1
- Parents:
- f40a309
- File:
-
- 1 edited
-
vlib/tsplot4.s (modified) (1 diff)
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vlib/tsplot4.s
rf40a309 r4f508e6 1 *------------------------------------------------------------------------------2 *tsplot4.s -- output characters to a 4-bit / pixel graphics window3 *with variable vertical pitch4 *Version 1 -- 1987-08-04 -- D.N. Lynx Crowe5 *(c) Copyright 1987 -- D.N. Lynx Crowe6 *------------------------------------------------------------------------------7 * 8 *tsplot4(obase, nw, fg, row, col, str. pitch)9 * int *obase, nw, fg, row, col, pitch;10 * char *str;11 * 12 *Outputs characters from the string at 'str' to an 'nw'13 *character wide 4-bit per pixel graphics window at 'obase'14 *at ('row','col'), using 'fg' as the foreground color.15 *Uses cgtable[][256] as the VSDD formatted character16 *generator table. Assumes 12 bit high characters in the17 *cgtable. Uses 'pitch' as the vertical spacing between18 *character rows. No error checks are done.19 *The string must fit the output area (no overlaps, single line).20 * 21 *------------------------------------------------------------------------------1 | ------------------------------------------------------------------------------ 2 | tsplot4.s -- output characters to a 4-bit / pixel graphics window 3 | with variable vertical pitch 4 | Version 1 -- 1987-08-04 -- D.N. Lynx Crowe 5 | (c) Copyright 1987 -- D.N. Lynx Crowe 6 | ------------------------------------------------------------------------------ 7 8 | tsplot4(obase, nw, fg, row, col, str. pitch) 9 | int |obase, nw, fg, row, col, pitch; 10 | char |str; 11 12 | Outputs characters from the string at 'str' to an 'nw' 13 | character wide 4-bit per pixel graphics window at 'obase' 14 | at ('row','col'), using 'fg' as the foreground color. 15 | Uses cgtable[][256] as the VSDD formatted character 16 | generator table. Assumes 12 bit high characters in the 17 | cgtable. Uses 'pitch' as the vertical spacing between 18 | character rows. No error checks are done. 19 | The string must fit the output area (no overlaps, single line). 20 21 | ------------------------------------------------------------------------------ 22 22 .text 23 * 23 24 24 .xdef _tsplot4 25 * 25 26 26 .xref _cgtable 27 * 28 *Argument offsets from a6:29 * 30 OBASE .equ 8 *LONG - Output area base address31 NW .equ 12 *WORD - Character width of output area32 FG .equ 14 *WORD - Foreground color33 ROW .equ 16 *WORD - Row34 COL .equ 18 *WORD - Column35 STR .equ 20 *LONG - String base address36 PITCH .equ 24 *WORD - Vertical spacing between rows37 * 38 *Program constant definitions:39 * 40 HPIX .equ 8 *Character width in pixels41 VPIX .equ 12 *Character height in pixels42 HCW .equ 4 *Horizontal character width (bytes)43 PSHIFT .equ 12 *Pixel shift into MS bits44 HSHIFT .equ 4 *Pixel right shift45 * 27 28 | Argument offsets from a6: 29 30 OBASE = 8 | LONG - Output area base address 31 NW = 12 | WORD - Character width of output area 32 FG = 14 | WORD - Foreground color 33 ROW = 16 | WORD - Row 34 COL = 18 | WORD - Column 35 STR = 20 | LONG - String base address 36 PITCH = 24 | WORD - Vertical spacing between rows 37 38 | Program constant definitions: 39 40 HPIX = 8 | Character width in pixels 41 VPIX = 12 | Character height in pixels 42 HCW = 4 | Horizontal character width (bytes) 43 PSHIFT = 12 | Pixel shift into MS bits 44 HSHIFT = 4 | Pixel right shift 45 46 46 .page 47 * 48 *Register usage:49 * 50 *d0 output word and scratch51 *d1 CG word and scratch52 *d2 pixel counter53 * 54 *d3 foreground color (in the 4 ms bits)55 *d4 background color (in the 4 ms bits)56 *d5 width of the area in bytes57 *d6 scan line counter58 * 59 *a0 CG table pointer60 *a1 output area scan line pointer61 *a2 input string character pointer62 * 63 *a3 output area character base pointer64 * 65 *a6 frame pointer66 *a7 stack pointer67 * 47 48 | Register usage: 49 50 | d0 output word and scratch 51 | d1 CG word and scratch 52 | d2 pixel counter 53 54 | d3 foreground color (in the 4 ms bits) 55 | d4 background color (in the 4 ms bits) 56 | d5 width of the area in bytes 57 | d6 scan line counter 58 59 | a0 CG table pointer 60 | a1 output area scan line pointer 61 | a2 input string character pointer 62 63 | a3 output area character base pointer 64 65 | a6 frame pointer 66 | a7 stack pointer 67 68 68 .page 69 * 70 _tsplot4: link a6,#0 *Link stack frames71 movem.l d3-d6/a3,-(a7) *Save registers we use72 move.w #PSHIFT,d1 *Set shift constant73 move.w FG(a6),d3 *Setup foreground color74 lsl.w d1,d3 *... in ms 4 bits of d3.W75 move.w NW(a6),d5 *Get line width in d5.W76 lsl.w #2,d5 *Multiply width by 4 for offset77 move.w ROW(a6),d0 *Calculate output address78 move.w PITCH(a6),d1 *... PITCH79 mulu d1,d0 * ... *ROW80 add.w #VPIX-1,d0 *... + VPIX-181 mulu d5,d0 * ... *NW82 clr.l d1 *...83 move.w COL(a6),d1 * ... +84 lsl.w #2,d1 * ... COL *485 add.l d1,d0 *...86 add.l OBASE(a6),d0 *... + OBASE87 movea.l d0,a3 *Leave output address in a388 movea.l STR(a6),a2 *Put string address in a289 * 90 cgl0: clr.l d0 *Clear out upper bits of d091 move.b (a2)+,d0 *Get next character92 beq cgl5 *Done if character EQ 093 * 94 movea.l a3,a1 *Establish output pointer in a195 adda.l #HCW,a3 *Update output pointer for next char.96 lea _cgtable,a0 *Establish CG pointer in a097 lsl.w #1,d0 * ... 2 *character98 adda.w d0,a0 *... + _cgtable address99 move.w #VPIX-1,d6 *Set scan line counter in d6100 * 69 70 _tsplot4: link a6,#0 | Link stack frames 71 movem.l d3-d6/a3,-(a7) | Save registers we use 72 move.w #PSHIFT,d1 | Set shift constant 73 move.w FG(a6),d3 | Setup foreground color 74 lsl.w d1,d3 | ... in ms 4 bits of d3.W 75 move.w NW(a6),d5 | Get line width in d5.W 76 lsl.w #2,d5 | Multiply width by 4 for offset 77 move.w ROW(a6),d0 | Calculate output address 78 move.w PITCH(a6),d1 | ... PITCH 79 mulu d1,d0 | ... | ROW 80 add.w #VPIX-1,d0 | ... + VPIX-1 81 mulu d5,d0 | ... | NW 82 clr.l d1 | ... 83 move.w COL(a6),d1 | ... + 84 lsl.w #2,d1 | ... COL | 4 85 add.l d1,d0 | ... 86 add.l OBASE(a6),d0 | ... + OBASE 87 movea.l d0,a3 | Leave output address in a3 88 movea.l STR(a6),a2 | Put string address in a2 89 90 cgl0: clr.l d0 | Clear out upper bits of d0 91 move.b (a2)+,d0 | Get next character 92 beq cgl5 | Done if character EQ 0 93 94 movea.l a3,a1 | Establish output pointer in a1 95 adda.l #HCW,a3 | Update output pointer for next char. 96 lea _cgtable,a0 | Establish CG pointer in a0 97 lsl.w #1,d0 | ... 2 | character 98 adda.w d0,a0 | ... + _cgtable address 99 move.w #VPIX-1,d6 | Set scan line counter in d6 100 101 101 .page 102 cgl1: move.w (a0),d1 *Get character generator word in d1103 move.w #(HPIX/2)-1,d2 *Set pixel counter in d2104 clr.l d4 *Get old output word as background105 move.w (a1),d4 *...106 swap d4 *...107 * 108 cgl2: lsr.w #HSHIFT,d0 *Shift output word right 1 pixel109 lsr.l #HSHIFT,d4 *Shift background word 1 pixel110 andi.l # $FFFFF000,d4 *Mask for upper 4 bits of d4.W111 btst.l #0,d1 *Check CG word ls bit112 beq cgl3 *Set background color if bit EQ 0113 * 114 or.w d3,d0 *OR foreground color into output word115 bra cgl4 *Go update CG word116 * 117 cgl3: or.w d4,d0 *OR background color into output word118 * 119 cgl4: lsr.w #1,d1 *Shift CG word right 1 pixel120 dbf d2,cgl2 *Loop for first 4 pixels121 * 122 move.w d0,(a1)+ *Store first output word in scan line123 move.w #(HPIX/2)-1,d2 *Set pixel counter in d2124 clr.l d4 *Get old output word as background125 move.w (a1),d4 *...126 swap d4 *...127 * 128 cgl2a: lsr.w #HSHIFT,d0 *Shift output word right 1 pixel129 lsr.l #HSHIFT,d4 *Shift background word 1 pixel130 andi.l # $FFFFF000,d4 *Mask for upper bits of d4.W131 btst.l #0,d1 *Check CG word ls bit132 beq cgl3a *Set background color if bit EQ 0133 * 134 or.w d3,d0 *OR foreground color into output word135 bra cgl4a *Go update CG word136 * 137 cgl3a: or.w d4,d0 *OR background color into output word138 * 139 cgl4a: lsr.w #1,d1 *Shift CG word right 1 pixel140 dbf d2,cgl2a *Loop for last 4 pixels141 * 142 move.w d0,(a1) *Store second output word in scan line143 suba.w d5,a1 *Update output pointer144 suba.w #2,a1 *...145 adda.l #512,a0 *Update CG pointer for next scan line146 dbf d6,cgl1 *Loop for all scan lines147 * 148 bra cgl0 *Loop for next character149 * 150 cgl5: movem.l (a7)+,d3-d6/a3 *Restore registers151 unlk a6 *Unlink stack frames152 rts *Return to caller153 * 102 cgl1: move.w (a0),d1 | Get character generator word in d1 103 move.w #(HPIX/2)-1,d2 | Set pixel counter in d2 104 clr.l d4 | Get old output word as background 105 move.w (a1),d4 | ... 106 swap d4 | ... 107 108 cgl2: lsr.w #HSHIFT,d0 | Shift output word right 1 pixel 109 lsr.l #HSHIFT,d4 | Shift background word 1 pixel 110 andi.l #0xFFFFF000,d4 | Mask for upper 4 bits of d4.W 111 btst.l #0,d1 | Check CG word ls bit 112 beq cgl3 | Set background color if bit EQ 0 113 114 or.w d3,d0 | OR foreground color into output word 115 bra cgl4 | Go update CG word 116 117 cgl3: or.w d4,d0 | OR background color into output word 118 119 cgl4: lsr.w #1,d1 | Shift CG word right 1 pixel 120 dbf d2,cgl2 | Loop for first 4 pixels 121 122 move.w d0,(a1)+ | Store first output word in scan line 123 move.w #(HPIX/2)-1,d2 | Set pixel counter in d2 124 clr.l d4 | Get old output word as background 125 move.w (a1),d4 | ... 126 swap d4 | ... 127 128 cgl2a: lsr.w #HSHIFT,d0 | Shift output word right 1 pixel 129 lsr.l #HSHIFT,d4 | Shift background word 1 pixel 130 andi.l #0xFFFFF000,d4 | Mask for upper bits of d4.W 131 btst.l #0,d1 | Check CG word ls bit 132 beq cgl3a | Set background color if bit EQ 0 133 134 or.w d3,d0 | OR foreground color into output word 135 bra cgl4a | Go update CG word 136 137 cgl3a: or.w d4,d0 | OR background color into output word 138 139 cgl4a: lsr.w #1,d1 | Shift CG word right 1 pixel 140 dbf d2,cgl2a | Loop for last 4 pixels 141 142 move.w d0,(a1) | Store second output word in scan line 143 suba.w d5,a1 | Update output pointer 144 suba.w #2,a1 | ... 145 adda.l #512,a0 | Update CG pointer for next scan line 146 dbf d6,cgl1 | Loop for all scan lines 147 148 bra cgl0 | Loop for next character 149 150 cgl5: movem.l (a7)+,d3-d6/a3 | Restore registers 151 unlk a6 | Unlink stack frames 152 rts | Return to caller 153 154 154 .end
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