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helper to render fonts outside video RAM, take 2

main
Kartik K. Agaram 1 year ago
parent
commit
0511b9fd11
  1. 43
      101screen.subx
  2. 41
      103grapheme.subx

43
101screen.subx

@ -6,6 +6,19 @@
== code
pixel-on-real-screen: # x: int, y: int, color: int
# . prologue
55/push-ebp
89/<- %ebp 4/r32/esp
#
(pixel-on-screen-buffer *Video-memory-addr *(ebp+8) *(ebp+0xc) *(ebp+0x10) 0x400 0x300)
$pixel-on-real-screen:end:
# . epilogue
89/<- %esp 5/r32/ebp
5d/pop-to-ebp
c3/return
# 'buffer' here is not a valid Mu type: a naked address without a length.
pixel-on-screen-buffer: # buffer: (addr byte), x: int, y: int, color: int, width: int, height: int
# . prologue
55/push-ebp
89/<- %ebp 4/r32/esp
@ -13,26 +26,26 @@ pixel-on-real-screen: # x: int, y: int, color: int
50/push-eax
51/push-ecx
# bounds checks
8b/-> *(ebp+8) 0/r32/eax
8b/-> *(ebp+0xc) 0/r32/eax # foo
3d/compare-eax-and 0/imm32
7c/jump-if-< $pixel-on-real-screen:end/disp8
3d/compare-eax-and 0x400/imm32/screen-width=1024
7d/jump-if->= $pixel-on-real-screen:end/disp8
8b/-> *(ebp+0xc) 0/r32/eax
7c/jump-if-< $pixel-on-screen-buffer:end/disp8
3b/compare 0/r32/eax *(ebp+0x18)
7d/jump-if->= $pixel-on-screen-buffer:end/disp8
8b/-> *(ebp+0x10) 0/r32/eax
3d/compare-eax-and 0/imm32
7c/jump-if-< $pixel-on-real-screen:end/disp8
3d/compare-eax-and 0x300/imm32/screen-height=768
7d/jump-if->= $pixel-on-real-screen:end/disp8
# eax = y*1024 + x
8b/-> *(ebp+0xc) 0/r32/eax
c1/shift 4/subop/left %eax 0xa/imm8
03/add-> *(ebp+8) 0/r32/eax
7c/jump-if-< $pixel-on-screen-buffer:end/disp8
3b/compare 0/r32/eax *(ebp+0x1c)
7d/jump-if->= $pixel-on-screen-buffer:end/disp8
# eax = y*width + x
8b/-> *(ebp+0x10) 0/r32/eax
0f af/multiply-> *(ebp+0x18) 0/r32/eax
03/add-> *(ebp+0xc) 0/r32/eax
# eax += location of frame buffer
03/add-> *Video-memory-addr 0/r32/eax
03/add-> *(ebp+8) 0/r32/eax
# *eax = color
8b/-> *(ebp+0x10) 1/r32/ecx
8b/-> *(ebp+0x14) 1/r32/ecx
88/byte<- *eax 1/r32/CL
$pixel-on-real-screen:end:
$pixel-on-screen-buffer:end:
# . restore registers
59/pop-to-ecx
58/pop-to-eax

41
103grapheme.subx

@ -15,6 +15,21 @@
# Doesn't update the cursor; where the cursor should go after printing the
# current grapheme is a higher-level concern.
draw-grapheme-on-real-screen: # g: grapheme, x: int, y: int, color: int, background-color: int
# . prologue
55/push-ebp
89/<- %ebp 4/r32/esp
#
(draw-grapheme-on-screen-buffer *Video-memory-addr *(ebp+8) *(ebp+0xc) *(ebp+0x10) *(ebp+0x14) *(ebp+0x18) 0x400 0x300)
$draw-grapheme-on-real-screen:end:
# . epilogue
89/<- %esp 5/r32/ebp
5d/pop-to-ebp
c3/return
# 'buffer' here is not a valid Mu type: a naked address without a length.
# 'x' and 'y' are in graphemes
# 'screen-width' and 'screen-height' are in pixels
draw-grapheme-on-screen-buffer: # buffer: (addr byte), g: grapheme, x: int, y: int, color: int, background-color: int, screen-width: int, screen-height: int
# . prologue
55/push-ebp
89/<- %ebp 4/r32/esp
@ -25,30 +40,30 @@ draw-grapheme-on-real-screen: # g: grapheme, x: int, y: int, color: int, backgr
53/push-ebx
56/push-esi
# esi = g
8b/-> *(ebp+8) 6/r32/esi
8b/-> *(ebp+0xc) 6/r32/esi
# if (g >= 128) return # characters beyond ASCII currently not supported
81 7/subop/compare %esi 0x80/imm32
7d/jump-if->= $draw-grapheme-on-real-screen:end/disp8
0f 8d/jump-if->= $draw-grapheme-on-screen-buffer:end/disp32
# var letter-bitmap/esi = font[g]
c1 4/subop/shift-left %esi 4/imm8
81 0/subop/add %esi Font/imm32
# var ycurr/edx: int = y*16
8b/-> *(ebp+0x10) 2/r32/edx
8b/-> *(ebp+0x14) 2/r32/edx
c1 4/subop/shift-left %edx 4/imm8
# var ymax/ebx: int = ycurr + 16
8b/-> *(ebp+0x10) 3/r32/ebx
8b/-> *(ebp+0x14) 3/r32/ebx
c1 4/subop/shift-left %ebx 4/imm8
81 0/subop/add %ebx 0x10/imm32
{
# if (ycurr >= ymax) break
39/compare %edx 3/r32/ebx
7d/jump-if->= break/disp8
0f 8d/jump-if->= break/disp32
# var xcurr/eax: int = x*8 + 7
8b/-> *(ebp+0xc) 0/r32/eax # font-width - 1
8b/-> *(ebp+0x10) 0/r32/eax # font-width - 1
c1 4/subop/shift-left %eax 3/imm8
05/add-to-eax 7/imm32
# var xmin/ecx: int = x*8
8b/-> *(ebp+0xc) 1/r32/ecx
8b/-> *(ebp+0x10) 1/r32/ecx
c1 4/subop/shift-left %ecx 3/imm8
# var row-bitmap/ebx: int = *letter-bitmap
53/push-ebx
@ -62,12 +77,12 @@ draw-grapheme-on-real-screen: # g: grapheme, x: int, y: int, color: int, backgr
# if LSB, draw a pixel in the given color
{
73/jump-if-not-CF break/disp8
(pixel-on-real-screen %eax %edx *(ebp+0x14))
eb/jump $draw-grapheme-on-real-screen:continue/disp8
(pixel-on-screen-buffer *(ebp+8) %eax %edx *(ebp+0x18) *(ebp+0x20) *(ebp+0x24))
eb/jump $draw-grapheme-on-screen-buffer:continue/disp8
}
# otherwise use the background color
(pixel-on-real-screen %eax %edx *(ebp+0x18))
$draw-grapheme-on-real-screen:continue:
(pixel-on-screen-buffer *(ebp+8) %eax %edx *(ebp+0x1c) *(ebp+0x20) *(ebp+0x24))
$draw-grapheme-on-screen-buffer:continue:
# --x
48/decrement-eax
#
@ -80,9 +95,9 @@ $draw-grapheme-on-real-screen:continue:
# next bitmap row
46/increment-esi
#
eb/jump loop/disp8
e9/jump loop/disp32
}
$draw-grapheme-on-real-screen:end:
$draw-grapheme-on-screen-buffer:end:
# . restore registers
5e/pop-to-esi
5b/pop-to-ebx

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