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Changeset 4f508e6 in buchla-68k for vlib/vcputs.s
- Timestamp:
- 07/01/2017 02:34:46 PM (7 years ago)
- Branches:
- master
- Children:
- 08e1da1
- Parents:
- f40a309
- File:
-
- 1 edited
-
vlib/vcputs.s (modified) (1 diff)
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vlib/vcputs.s
rf40a309 r4f508e6 1 *------------------------------------------------------------------------------2 *vcputs.s -- output a character string to a 4-bit per pixel graphics window3 *Version 3 -- 1987-07-31 -- D.N. Lynx Crowe4 *(c) Copyright 1987 -- D.N. Lynx Crowe5 *------------------------------------------------------------------------------6 * 7 *vcputs(obase, nw, fg, bg, row, col, str)8 * int *obase, nw, fg, bg, row, col;9 * char *str;10 * 11 *Outputs characters from the string at 'str' to an 'nw'12 *character wide 4-bit per pixel graphics window at 'obase'13 *at ('row','col'), using 'fg' as the foreground color, and14 *'bg' as the background color. Uses cgtable[][256] as the15 *VSDD formatted character generator table.16 *No error checks are done.17 * 18 *------------------------------------------------------------------------------1 | ------------------------------------------------------------------------------ 2 | vcputs.s -- output a character string to a 4-bit per pixel graphics window 3 | Version 3 -- 1987-07-31 -- D.N. Lynx Crowe 4 | (c) Copyright 1987 -- D.N. Lynx Crowe 5 | ------------------------------------------------------------------------------ 6 7 | vcputs(obase, nw, fg, bg, row, col, str) 8 | int |obase, nw, fg, bg, row, col; 9 | char |str; 10 11 | Outputs characters from the string at 'str' to an 'nw' 12 | character wide 4-bit per pixel graphics window at 'obase' 13 | at ('row','col'), using 'fg' as the foreground color, and 14 | 'bg' as the background color. Uses cgtable[][256] as the 15 | VSDD formatted character generator table. 16 | No error checks are done. 17 18 | ------------------------------------------------------------------------------ 19 19 .text 20 * 20 21 21 .xdef _vcputs 22 * 22 23 23 .xref _cgtable 24 * 25 *Argument offsets from a6:26 * 27 OBASE .equ 8 *Output area base address28 NW .equ 12 *Character width of output area29 FG .equ 14 *Foreground color30 BG .equ 16 *Background color31 ROW .equ 18 *Row32 COL .equ 20 *Column33 STR .equ 22 *String base address34 * 35 *Program constant definitions:36 * 37 HPIX .equ 8 *Character width in pixels38 VPIX .equ 12 *Character height in pixels39 HCW .equ 4 *Horizontal character width (bytes)40 PSHIFT .equ 12 *Pixel shift into MS bits41 HSHIFT .equ 4 *Pixel right shift42 * 24 25 | Argument offsets from a6: 26 27 OBASE = 8 | Output area base address 28 NW = 12 | Character width of output area 29 FG = 14 | Foreground color 30 BG = 16 | Background color 31 ROW = 18 | Row 32 COL = 20 | Column 33 STR = 22 | String base address 34 35 | Program constant definitions: 36 37 HPIX = 8 | Character width in pixels 38 VPIX = 12 | Character height in pixels 39 HCW = 4 | Horizontal character width (bytes) 40 PSHIFT = 12 | Pixel shift into MS bits 41 HSHIFT = 4 | Pixel right shift 42 43 43 .page 44 * 45 *Register usage:46 * 47 *d0 output word and scratch48 *d1 CG word and scratch49 *d2 pixel counter50 * 51 *d3 foreground color (in the 4 ms bits)52 *d4 background color (in the 4 ms bits)53 *d5 width of the area in bytes54 *d6 scan line counter55 * 56 *a0 CG table pointer57 *a1 output area scan line pointer58 *a2 input string character pointer59 * 60 *a3 output area character base pointer61 * 44 45 | Register usage: 46 47 | d0 output word and scratch 48 | d1 CG word and scratch 49 | d2 pixel counter 50 51 | d3 foreground color (in the 4 ms bits) 52 | d4 background color (in the 4 ms bits) 53 | d5 width of the area in bytes 54 | d6 scan line counter 55 56 | a0 CG table pointer 57 | a1 output area scan line pointer 58 | a2 input string character pointer 59 60 | a3 output area character base pointer 61 62 62 .page 63 * 64 _vcputs: link a6,#0 *Link stack frames65 movem.l d3-d6/a3,-(a7) *Save registers we use66 move.w #PSHIFT,d1 *Set shift constant67 move.w FG(a6),d3 *Setup foreground color68 lsl.w d1,d3 *... in ms 4 bits of d3.W69 move.w BG(a6),d4 *Setup background color70 lsl.w d1,d4 *... in ms 4 bits of d4.W71 move.w NW(a6),d5 *Get line width in d5.W72 lsl.w #2,d5 *Multiply width by 4 for offset73 move.w ROW(a6),d0 *Calculate output address74 move.w #VPIX,d1 *... VPIX75 mulu d1,d0 * ... *ROW76 add.w #VPIX-1,d0 *... + VPIX-177 mulu d5,d0 * ... *NW78 clr.l d1 *...79 move.w COL(a6),d1 * ... +80 lsl.w #2,d1 * ... COL *481 add.l d1,d0 *...82 add.l OBASE(a6),d0 *... + OBASE83 movea.l d0,a3 *Leave output address in a384 movea.l STR(a6),a2 *Put string address in a285 * 86 cgl0: clr.l d0 *Clear out upper bits of d087 move.b (a2)+,d0 *Get next character88 beq cgl5 *Done if character EQ 089 * 90 movea.l a3,a1 *Establish output pointer in a191 adda.l #HCW,a3 *Update output pointer for next char.92 lea _cgtable,a0 *Establish CG pointer in a093 lsl.w #1,d0 * ... 2 *character94 adda.w d0,a0 *... + _cgtable address95 move.w #VPIX-1,d6 *Set scan line counter in d696 * 63 64 _vcputs: link a6,#0 | Link stack frames 65 movem.l d3-d6/a3,-(a7) | Save registers we use 66 move.w #PSHIFT,d1 | Set shift constant 67 move.w FG(a6),d3 | Setup foreground color 68 lsl.w d1,d3 | ... in ms 4 bits of d3.W 69 move.w BG(a6),d4 | Setup background color 70 lsl.w d1,d4 | ... in ms 4 bits of d4.W 71 move.w NW(a6),d5 | Get line width in d5.W 72 lsl.w #2,d5 | Multiply width by 4 for offset 73 move.w ROW(a6),d0 | Calculate output address 74 move.w #VPIX,d1 | ... VPIX 75 mulu d1,d0 | ... | ROW 76 add.w #VPIX-1,d0 | ... + VPIX-1 77 mulu d5,d0 | ... | NW 78 clr.l d1 | ... 79 move.w COL(a6),d1 | ... + 80 lsl.w #2,d1 | ... COL | 4 81 add.l d1,d0 | ... 82 add.l OBASE(a6),d0 | ... + OBASE 83 movea.l d0,a3 | Leave output address in a3 84 movea.l STR(a6),a2 | Put string address in a2 85 86 cgl0: clr.l d0 | Clear out upper bits of d0 87 move.b (a2)+,d0 | Get next character 88 beq cgl5 | Done if character EQ 0 89 90 movea.l a3,a1 | Establish output pointer in a1 91 adda.l #HCW,a3 | Update output pointer for next char. 92 lea _cgtable,a0 | Establish CG pointer in a0 93 lsl.w #1,d0 | ... 2 | character 94 adda.w d0,a0 | ... + _cgtable address 95 move.w #VPIX-1,d6 | Set scan line counter in d6 96 97 97 .page 98 cgl1: move.w (a0),d1 *Get character generator word in d199 move.w #(HPIX/2)-1,d2 *Set pixel counter in d2100 * 101 cgl2: lsr.w #HSHIFT,d0 *Shift output word right 1 pixel102 btst.l #0,d1 *Check CG word ls bit103 beq cgl3 *Set background color if bit EQ 0104 * 105 or.w d3,d0 *OR foreground color into output word106 bra cgl4 *Go update CG word107 * 108 cgl3: or.w d4,d0 *OR background color into output word109 * 110 cgl4: lsr.w #1,d1 *Shift CG word right 1 pixel111 dbf d2,cgl2 *Loop for first 4 pixels112 * 113 move.w d0,(a1)+ *Store first output word in scan line114 move.w #(HPIX/2)-1,d2 *Set pixel counter in d2115 * 116 cgl2a: lsr.w #HSHIFT,d0 *Shift output word right 1 pixel117 btst.l #0,d1 *Check CG word ls bit118 beq cgl3a *Set background color if bit EQ 0119 * 120 or.w d3,d0 *OR foreground color into output word121 bra cgl4a *Go update CG word122 * 123 cgl3a: or.w d4,d0 *OR background color into output word124 * 125 cgl4a: lsr.w #1,d1 *Shift CG word right 1 pixel126 dbf d2,cgl2a *Loop for last 4 pixels127 * 128 move.w d0,(a1) *Store second output word in scan line129 suba.w d5,a1 *Update output pointer130 suba.w #2,a1 *...131 adda.l #512,a0 *Update CG pointer for next scan line132 dbf d6,cgl1 *Loop for all scan lines133 * 134 bra cgl0 *Loop for next character135 * 136 cgl5: movem.l (a7)+,d3-d6/a3 *Restore registers137 unlk a6 *Unlink stack frames138 rts *Return to caller139 * 98 cgl1: move.w (a0),d1 | Get character generator word in d1 99 move.w #(HPIX/2)-1,d2 | Set pixel counter in d2 100 101 cgl2: lsr.w #HSHIFT,d0 | Shift output word right 1 pixel 102 btst.l #0,d1 | Check CG word ls bit 103 beq cgl3 | Set background color if bit EQ 0 104 105 or.w d3,d0 | OR foreground color into output word 106 bra cgl4 | Go update CG word 107 108 cgl3: or.w d4,d0 | OR background color into output word 109 110 cgl4: lsr.w #1,d1 | Shift CG word right 1 pixel 111 dbf d2,cgl2 | Loop for first 4 pixels 112 113 move.w d0,(a1)+ | Store first output word in scan line 114 move.w #(HPIX/2)-1,d2 | Set pixel counter in d2 115 116 cgl2a: lsr.w #HSHIFT,d0 | Shift output word right 1 pixel 117 btst.l #0,d1 | Check CG word ls bit 118 beq cgl3a | Set background color if bit EQ 0 119 120 or.w d3,d0 | OR foreground color into output word 121 bra cgl4a | Go update CG word 122 123 cgl3a: or.w d4,d0 | OR background color into output word 124 125 cgl4a: lsr.w #1,d1 | Shift CG word right 1 pixel 126 dbf d2,cgl2a | Loop for last 4 pixels 127 128 move.w d0,(a1) | Store second output word in scan line 129 suba.w d5,a1 | Update output pointer 130 suba.w #2,a1 | ... 131 adda.l #512,a0 | Update CG pointer for next scan line 132 dbf d6,cgl1 | Loop for all scan lines 133 134 bra cgl0 | Loop for next character 135 136 cgl5: movem.l (a7)+,d3-d6/a3 | Restore registers 137 unlk a6 | Unlink stack frames 138 rts | Return to caller 139 140 140 .end
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