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vga_scanline_driver_320x240.s
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/*
* VGA Scanline Driver 320x240
*
* Author: Marko Lukat
* Modified by: Marco Maccaferri
*
* MIT Licensed.
*/
.pasm
.compress off
.section .cog_vga_320x240_video_driver, "ax"
.equ zero, $1F0 // par (dst only)
.equ vpin, $0FC // pin group mask
.equ vgrp, 2 // pin group
.equ sgrp, 2 // pin group sync
.equ hv_idle, $01010101 * %11 // h/v sync inactive
.equ res_x, 320 // |
.equ res_y, 240 // |
.equ res_m, 1 // UI support
.org 0
driver call #setup // -4 once (replaced by 16 entry table)
res 15
mov dira, mask // drive outputs
// horizontal timing 320(640) 1(16) 6(96) 3(48)
// vertical timing 240(480) 10(10) 2(2) 33(33)
vsync mov lcnt, #1 // |
mov ecnt, #10
call #blank wc // front porch
djnz ecnt, #$-1
xor sync, #$0101 // active
//
call #blank wc // |
call #blank wc // vertical sync
xor sync, #$0101 // inactive
mov ecnt, #20
call #blank wc // back porch
djnz ecnt, #$-1
wrword zero, par // reset line counter
mov ecnt, #12
_last call #blank wc // back porch
djnz ecnt, #$-1
// The following instruction (performing unsigned borrow) exploits the
// fact that a ret insn has its wr bit cleared and is therefore unsigned
// smaller than a call (wr set).
//
// call #blank %010111_001i_cccc_ddddddddd_sssssssss
// ret %010111_000i_cccc_ddddddddd_sssssssss
jmpret blank_ret, _last wc // last blank line done manually
// to start pixel loading
// Vertical sync chain done, do visible area.
mov scnt, #res_y
mov ecnt, #15 // load 15 longs while emitting line
_loop mov outa, idle // take over sync lines (&&)
mov vcfg, vcfg_norm // disconnect sync from video h/w (&&)
mov vscl, hvis // visible line 2/8
call #emit wc // carry clear
mov outa, idle // take over sync lines (&&)
mov vcfg, vcfg_norm // disconnect sync from video h/w (&&)
mov vscl, hvis // visible line 2/8
call #emit wc // carry clear
djnz scnt, #_loop // repeat for all lines
jmp #vsync // next frame
blank mov vscl, line // 256/640
waitvid sync, #0
movd sub7, #one+79 // |
movd sub1, #one+78 // |
mov temp, #320 -1 // |
mov frqb, buf0 // always use primary
shr frqb, #1 // added twice #1{/2}
if_c call #load wc // load first line
mov vscl, wrap // horizontal sync
waitvid sync, wrap_value
mov cnt, cnt // record sync point
add cnt, #9+360 // | #9{14}+360
waitcnt cnt, #0 // cover front+sync (&&)
blank_ret ret
// While displaying a line the emitter fetches the next scanline. The visible
// part of the scanline loads 15 longs each, horizontal sync will load the
// remaining 26/24 longs (even/odd). 15-26-15-24
secondary waitvid vier, #%%3210
rdlong temp, addr
primary waitvid one-$01, #%%3210 // in place E
mov two-$01, temp // T
emit mov zwei, one+$01 // B
mov drei, one+$02 // C
mov vier, one+$03 // D
waitvid one+$00, #%%3210 // in place A
movs $+3, cnt
andn $+2, #%111110000
add addr, #4 // advance address for next load
jmp 0-0 // select target
_1st waitvid zwei, #%%3210
rdlong temp, addr
waitvid drei, #%%3210
add primary+5, dst5 // A++
add primary+2, #5 // B++
add primary+3, #5 // C++
add primary+4, #5 // D++
waitvid vier, #%%3210
add primary+0, dst5 // E++
add primary+1, dst1 // T++
djnz ecnt, #primary
_1st_tail waitvid one+$4A, #%%3210 // emit one/two[74]
jmp splice
_2nd waitvid zwei, #%%3210
add primary+5, dst5 // A++
add primary+2, #5 // B++
add primary+3, #5 // C++
add primary+4, #5 // D++
waitvid drei, #%%3210
rdlong temp, addr
waitvid vier, #%%3210
add primary+0, dst5 // E++
add primary+1, dst1 // T++
djnz ecnt, #primary
_2nd_tail waitvid one+$4A, #%%3210 // emit one/two[74]
jmp splice
_3rd waitvid zwei, #%%3210
add primary+5, dst5 // A++
add primary+2, #5 // B++
add primary+3, #5 // C++
add primary+4, #5 // D++
waitvid drei, #%%3210
add primary+0, dst5 // E++
add primary+1, dst1 // T++
djnz ecnt, #secondary
waitvid vier, #%%3210 // emit one/two[73]
rdlong temp, addr
_3rd_tail waitvid one+$4A, #%%3210 // emit one/two[74]
jmp splice
splice hubop $, com0
com0 mov two+$0E, temp // last write
movs splice, #com1
movd primary+1, #two+$28 // T==
waitvid one+$4B, #%%3210 // emit one[75]
movd primary+5, #one+$00 // A==
movs primary+2, #one+$01 // B==
movs primary+3, #one+$02 // C==
movs primary+4, #one+$03 // D==
waitvid one+$4C, #%%3210 // emit one[76]
movd primary+0, #one-$01 // E==
// nop
// nop
// nop
waitvid one+$4D, #%%3210 // emit one[77]
movd sub7, #two+40
movd sub1, #two+39
mov temp, #104 -1 // 26 longs
add addr, #4
waitvid one+$4E, #%%3210 // emit one[78]
mov frqb, addr
shr frqb, #1 // added twice #1{/2}
add addr, #104 -4 // counter early advance
add lcnt, #1 // next line index
waitvid one+$4F, #%%3210 // emit one[79]
jmpret zero, #emit_tail wc,nr // carry set
com1 mov two+$37, temp // last write
movs splice, #com2
movd primary+1, #one-$01 // T==
waitvid one+$4B, #%%3210 // emit one[75]
movd primary+5, #two+$00 // A==
movs primary+2, #two+$01 // B==
movs primary+3, #two+$02 // C==
movs primary+4, #two+$03 // D==
waitvid one+$4C, #%%3210 // emit one[76]
movd primary+0, #two-$01 // E==
movd _1st_tail, #two+$4A
movd _2nd_tail, #two+$4A
movd _3rd_tail, #two+$4A
waitvid one+$4D, #%%3210 // emit one[77]
movd sub7, #two+79
movd sub1, #two+78
mov temp, #96 -1 // 24 longs
add addr, #4
waitvid one+$4E, #%%3210 // emit one[78]
mov frqb, addr
shr frqb, #1 // added twice #1{/2}
mov addr, buf0 // fill primary buffer next
sub addr, #4 // counter early advance
waitvid one+$4F, #%%3210 // emit one[79]
jmp #emit_skip
com2 mov one+$0E, temp // last write
movs splice, #com3
movd primary+1, #one+$28 // T==
waitvid two+$4B, #%%3210 // emit two[75]
movd primary+5, #two+$00 // A==
movs primary+2, #two+$01 // B==
movs primary+3, #two+$02 // C==
movs primary+4, #two+$03 // D==
waitvid two+$4C, #%%3210 // emit two[76]
movd primary+0, #two-$01 // E==
// nop
// nop
// nop
waitvid two+$4D, #%%3210 // emit two[77]
movd sub7, #one+40
movd sub1, #one+39
mov temp, #104 -1 // 26 longs
add addr, #4
waitvid two+$4E, #%%3210 // emit two[78]
mov frqb, addr
shr frqb, #1 // added twice #1{/2}
add addr, #104 -4 // counter early advance
add lcnt, #1 // next line index
waitvid two+$4F, #%%3210 // emit two[79]
jmpret zero, #emit_tail wc,nr // carry set
com3 mov one+$37, temp // last write
movs splice, #com0
movd primary+1, #two-$01 // T==
waitvid two+$4B, #%%3210 // emit two[75]
movd primary+5, #one+$00 // A==
movs primary+2, #one+$01 // B==
movs primary+3, #one+$02 // C==
movs primary+4, #one+$03 // D==
waitvid two+$4C, #%%3210 // emit two[76]
movd primary+0, #one-$01 // E==
movd _1st_tail, #one+$4A
movd _2nd_tail, #one+$4A
movd _3rd_tail, #one+$4A
waitvid two+$4D, #%%3210 // emit two[77]
movd sub7, #one+79
movd sub1, #one+78
mov temp, #96 -1 // 24 longs
add addr, #4
waitvid two+$4E, #%%3210 // emit two[78]
mov frqb, addr
shr frqb, #1 // added twice #1{/2}
mov addr, buf1 // fill secondary buffer next
sub addr, #4 // counter early advance
waitvid two+$4F, #%%3210 // emit two[79]
// jmp #emit_skip
emit_skip cmp scnt, #2 wc // last line -> no 3rd party override
emit_tail mov ecnt, #15 // restore load counter
mov vscl, wrap // |
waitvid sync, wrap_value // chain horizontal sync
mov vcfg, vcfg_sync // drive/change sync lines (&&)
mov outa, #0 // stop interfering (&&)
// Loader is embedded here for speed reasons, also used during last blank line.
load mov phsb, temp // 8n + 7
sub7 rdlong 0-0, phsb // |
sub sub7, dst2 // |
sub phsb, #7 wz // |
sub1 rdlong 0-0, phsb // |
sub sub1, dst2 // |
if_nz djnz phsb, #sub7 // sub #7/djnz (Thanks Phil!)
{extn} if_nc rdword temp, extn wz // fetch optional 3rd party buffer
{extn} if_a mov addr, temp // a = nc & nz
{extn} if_a sub addr, #4 // |
{extn} if_nc wrlong lcnt, extn // line has been fetched
load_ret
emit_ret ret
//{odd lines} djnz scnt, #:loop // repeat for all lines
//
// :loop mov outa, idle // take over sync lines (&&)
// mov vcfg, vcfg_norm // disconnect sync from video h/w (&&)
// mov vscl, hvis // visible line 2/8
//
// call #emit
//
// emit mov zwei, one+$01 // B
// mov drei, one+$02 // C
// mov vier, one+$03 // D
// waitvid one+$00, #%%3210 // in place A
// The horizontal sync part takes 160 pixel clocks (508.4 clock cycles @80MHz).
// We spend 7 + 11/12*4 in normal insns plus an additional 26/24 hub windows for
// final pixel loading. Which gives us a worst case timing of
// - 51 + 26*16 + 0..15 = 482
// - 55 + 24*16 + 0..15 = 454
// with 1/3 remaining hub window(s) for even/odd lines respectively {extn}.
// initialised data and/or presets
idle long (hv_idle & $00FF) << (sgrp * 8)
sync long (hv_idle ^ $0200) & $FFFF
wrap_value long $1554 // horizontal sync pulse %%0001111110
wrap long 16 << 12 | 160 // 16/160
hvis long 2 << 12 | 8 // 2/8
line long 0 << 12 | 640 // 256/640
vcfg_norm long %0_01_1_00_000 << 23 | vgrp << 9 | vpin
vcfg_sync long %0_01_1_00_000 << 23 | sgrp << 9 | %11
mask long vpin << (vgrp * 8) | %11 << (sgrp * 8)
dst1 long 1 << 9 // dst +/-= 1
dst2 long 2 << 9 // dst +/-= 2
dst5 long 5 << 9 // dst +/-= 5
buf0 long $7EC0 // |
buf1 long $7EC0 // double buffer reference
extn long +2
// Stuff below is re-purposed for temporary storage.
setup rdlong temp, par // +0 =
neg href, cnt // +8 hub window reference (%%)
shr temp, #16 // -4 secondary ...
rdword temp, par // +0 = primary buffer
add href, #3 + 15 // -4 |
and href, #%1111 // +0 = (15 - (H - 3)) & 15
add copy, href // apply offset
mov ecnt, #16 // all possible hub offsets
copy mov $000, dist // |
add copy, d1s1 // |
djnz ecnt, #copy // transfer [shifted] table
mov addr, buf1 // address starts as secondary buffer
sub addr, #4 // counter early advance
add extn, par // 3rd party buffer reference
wrlong zero, par // acknowledge buffers
// Upset video h/w and relatives.
movi ctrb, #%0_11111_000 // LOGIC always (loader support)
movi ctra, #%0_00001_101 // PLL, VCO/4
mov frqa, frqx // 25.175MHz
mov vscl, hvis // 2/8
mov vcfg, vcfg_sync // VGA, 4 colour mode
// Setup complete, do the heavy lifting upstairs ...
setup_ret ret
// hub access distribution table valid for
// 25/26 cycles between WHOPs, 80MHz
dist long _2nd, _2nd, _2nd ,_2nd ,_2nd ,_2nd, _3rd, _3rd
long _1st, _1st, _1st, _1st, _1st, _1st, _1st, _1st
long _2nd, _2nd, _2nd ,_2nd ,_2nd ,_2nd, _3rd, _3rd
long _1st, _1st, _1st, _1st, _1st, _1st, _1st
frqx long $1423D70A
d1s1 long 1 << 9 | 1 // dst/src +/-= 1
// uninitialised data and/or temporaries
ecnt res 1 // element count
href res 1 // hub window reference < setup +1 (%%)
addr res 1 // colour buffer reference
lcnt res 1 // line counter
scnt res 1 // scanlines
temp res 1
zwei res 1
drei res 1
vier res 1
one res 80
two // all locations from here are reserved
// for the second scanline buffer
fit
/*
* TERMS OF USE: MIT License
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy,
* modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software
* is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
* WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/