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PentagonRenderer.asm
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PentagonRenderer.asm
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ASSUME ESI: PTR SpectrumGfx
PentagonPrepTopBorder:
mov [esi].ScreenVector, OFFSET PE_DrawTopBorder
mov [esi].UDCnt, 320/2
Align 16
PE_DrawTopBorder:
mov eax, [esi].BorderColour
PE_DrawTopBorder_1:
inc [esi].WaitTState
cmp ax, [edi]
jne PE_DTB_Changed
add edi, 2
dec [esi].UDCnt
jz PE_NextTopBorderLine
cmp ebx, [esi].WaitTState
jnc PE_DrawTopBorder_1
ret
PE_DTB_Changed:
mov [esi].ScreenVector, OFFSET PE_DrawTopBorder_Write
mov byte ptr [ebp], 1
mov [esi].FrameChanged, TRUE
jmp PE_DTB_Write
Align 16
PE_DrawTopBorder_Write:
mov eax, [esi].BorderColour
PE_DrawTopBorder_2:
inc [esi].WaitTState
PE_DTB_Write:
mov [edi], ax
add edi, 2
dec [esi].UDCnt
jz PE_NextTopBorderLine
cmp ebx, [esi].WaitTState
jnc PE_DrawTopBorder_2
ret
Align 4
PE_NextTopBorderLine:
NEXTSCANLINEADDR
mov eax, [esi].ScanTState
add eax, MACHINE.ScanlineCycles
mov [esi].ScanTState, eax
mov [esi].WaitTState, eax
add ebp, 3
dec [esi].TopBorderCnt
jz PE_PrepLeftBorder ; top border finished
mov [esi].ScreenVector, OFFSET PentagonPrepTopBorder
ret
; start actual screen area
Align 4
PE_PrepLeftBorder:
mov [esi].ScreenVector, OFFSET PE_DrawLeftBorder
mov [esi].UDCnt, 32/2
ret
Align 16
PE_DrawLeftBorder:
mov eax, [esi].BorderColour
PE_DrawLB1: inc [esi].WaitTState
.if ax != [edi]
mov [edi], ax
mov byte ptr [ebp], 1
mov [esi].FrameChanged, TRUE
.endif
add edi, 2
dec [esi].UDCnt
jz PE_PrepDisplayLine
cmp ebx, [esi].WaitTState
jnc PE_DrawLB1
ret
Align 4
PE_PrepDisplayLine:
inc ebp
sub [esi].WaitTState, 4
mov [esi].UDCnt, 16
mov [esi].FetchCycle, 0
mov [esi].ScreenVector, OFFSET PE_DrawDisplayLine
; prepare display/attr offsets for this scanline
mov eax, [DisplayTablePtr]
mov ecx, [eax]
mov eax, [eax+4]
add [DisplayTablePtr], 8
mov [esi].DisplayOffset, ecx
mov [esi].AttrOffset, eax
ret
Align 16
PE_DrawDisplayLine:
switch [esi].FetchCycle
add [esi].FetchCycle, 1
add [esi].WaitTState, 1
FETCHCYCLEOFFSET = 2
FETCHCYCLEOFFSET = FETCHCYCLEOFFSET - 1 ; safe to assume that the ULA address bus is loaded one cycle before sampling the data bus?
case FETCHCYCLEOFFSET
mov eax, [esi].DisplayOffset
add eax, [esi].zxDisplayOrg
mov al, [eax]
mov [esi].DisplayByte, al
case FETCHCYCLEOFFSET+1
mov eax, [esi].AttrOffset
add eax, [esi].zxDisplayOrg
mov al, [eax]
mov [esi].AttrByte, al
call Render_Pentagon_Character
case FETCHCYCLEOFFSET+2
mov eax, [esi].DisplayOffset
add eax, [esi].zxDisplayOrg
mov al, [eax]
mov [esi].DisplayByte, al
case FETCHCYCLEOFFSET+3
mov eax, [esi].AttrOffset
add eax, [esi].zxDisplayOrg
mov al, [eax]
mov [esi].AttrByte, al
call Render_Pentagon_Character
case 7
mov [esi].FetchCycle, 0
dec [esi].UDCnt
jz PE_PrepRightBorder
endsw
cmp ebx, [esi].WaitTState
jnc PE_DrawDisplayLine
ret
Align 4
PE_PrepRightBorder:
inc ebp
add [esi].WaitTState, 4
mov [esi].ScreenVector, OFFSET PE_DrawRightBorder
mov [esi].UDCnt, 32/2
ret
Align 16
PE_DrawRightBorder:
mov eax, [esi].BorderColour
PE_DrawRB1: inc [esi].WaitTState
.if ax != [edi]
mov [edi], ax
mov byte ptr [ebp], 1
mov [esi].FrameChanged, TRUE
.endif
add edi, 2
dec [esi].UDCnt
jz PE_PrepNextDisplayLine
cmp ebx, [esi].WaitTState
jnc PE_DrawRB1
ret
Align 4
PE_PrepNextDisplayLine:
NEXTSCANLINEADDR
inc [esi].CurrDisplayLine
inc ebp
mov edx, [esi].ScanTState
add edx, MACHINE.ScanlineCycles
mov [esi].ScanTState, edx
mov [esi].WaitTState, edx
cmp [esi].CurrDisplayLine, 192
jnc PE_PrepBottomBorder
mov [esi].ScreenVector, OFFSET PE_PrepLeftBorder
ret
Align 4
PE_PrepBottomBorder:
mov [esi].ScreenVector, OFFSET PE_DrawBottomBorder
mov [esi].UDCnt, 320/2
ret
Align 16
PE_DrawBottomBorder:
mov eax, [esi].BorderColour
PE_DrawBottomBorder_1:
inc [esi].WaitTState
cmp ax, [edi]
jne PE_DBB_Changed
add edi, 2
dec [esi].UDCnt
jz PE_NextBottomBorderLine
cmp ebx, [esi].WaitTState
jnc PE_DrawBottomBorder_1
ret
PE_DBB_Changed:
mov [esi].ScreenVector, OFFSET PE_DrawBottomBorder_Write
mov byte ptr [ebp], 1
mov [esi].FrameChanged, TRUE
jmp PE_DBB_Write
Align 16
PE_DrawBottomBorder_Write:
mov eax, [esi].BorderColour
PE_DrawBottomBorder_2:
inc [esi].WaitTState
PE_DBB_Write:
mov [edi], ax
add edi, 2
dec [esi].UDCnt
jz PE_NextBottomBorderLine
cmp ebx, [esi].WaitTState
jnc PE_DrawBottomBorder_2
ret
Align 4
PE_NextBottomBorderLine:
NEXTSCANLINEADDR
mov eax, [esi].ScanTState
add eax, MACHINE.ScanlineCycles
mov [esi].ScanTState, eax
mov [esi].WaitTState, eax
add ebp, 3
dec [esi].BottomBorderCnt
jz PE_VerticalRetrace ; bottom border finished
mov [esi].ScreenVector, OFFSET PE_PrepBottomBorder
ret
Align 4
PE_VerticalRetrace:
mov [esi].ScreenVector, OFFSET UScrExit
mov [esi].WaitTState, 180000
ret
Render_Pentagon_Character:
movzx eax, [esi].AttrByte ; eax = attribute byte
movzx ecx, [esi].DisplayByte ; ecx = display byte
test eax, 128
je @F ; flash bit clear
and eax, 127 ; clear Flash bit
xor cl, [esi].FlashInverterByte
@@: shl eax, 11 ; * 2048 (256 entries per colour * 8 bytes/entry)
lea eax, [eax+ecx*8] ; 8 bytes/entry
add eax, [esi].ptrSpecColourTable ; offset into DirectDraw colour mapping table
mov ecx, [eax] ; pick up 8 pixel colour values
mov eax, [eax+4]
.if ecx != [edi]
mov [edi], ecx
mov byte ptr [ebp], 1
mov [esi].FrameChanged, TRUE
.endif
.if eax != [edi+4]
mov [edi+4], eax
mov byte ptr [ebp], 1
mov [esi].FrameChanged, TRUE
.endif
add edi, 8
add [esi].DisplayOffset, 1
add [esi].AttrOffset, 1
ret
ASSUME ESI:NOTHING