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xrick2gs
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blit.c: better PEI blitter, get rid of TSC and TDC instructions (track A and C states, so we can just adc #immediate when we need to adjust the DP or S register), instead of RTS, use jmp #immediate to return

This commit is contained in:
dwsJason 2018-08-25 22:59:42 -04:00
parent 7ad65f0f9c
commit 8c6b911c6e
1 changed files with 40 additions and 25 deletions
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65
bin/blit/source/blit.c
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@ -86,7 +86,8 @@ void CompileBlockTRB(RAWDATA *result, int x, int width)
}
}
clocks += AddLine("","RTL"," ;%d cycles",clocks+6,6);
// clocks += AddLine("","RTL"," ;%d cycles",clocks+6,6);
clocks += AddLine("","JMP","BRET ;%d cycles",clocks+3,3);
}
RAWDATA* CompileTRB()
@ -118,6 +119,23 @@ RAWDATA* CompileTRB()
return result;
}
//A = ADC(A,delta,C);
int ADC(int A, int delta, int* C)
{
u32 uA = A &0xFFFF;
u32 uD = delta&0xFFFF;
int result = A + delta + *C;
u32 uResult = uA+uD+*C;
*C = (uResult>>16) & 1;
return result;
}
/*
lda #$2000
tcd
@ -144,10 +162,14 @@ RAWDATA* CompileTRB()
void CompileBlockPEI(RAWDATA *result, int x, int width)
{
int clocks = 0;
int A = 0; // What's in the accumulator
int C = 0;
clocks += AddLine("","TCD"," ; Set DP ",0,2);
clocks += AddLine("","ADC","#%d",((x+width)>>1)+1,3);
clocks += AddLine("","TCS","",0,2);
clocks += AddLine("","TCD"," ; Set DP $%04X",A,2);
clocks += AddLine("","ADC","#%d",((x+width)>>1)-1,3);
A+=((x+width)>>1)-1;
int S=A;
clocks += AddLine("","TCS"," ; Set S $%04X",A,2);
int dp = 0;
@ -155,32 +177,20 @@ void CompileBlockPEI(RAWDATA *result, int x, int width)
{
int p = y * 160;
//for (int xs = x; xs < (x+width) ; xs+=4)
for (int xs = 316; xs >= 0; xs-=4)
{
int xbyte = (xs>>1) + p;
#if 0
if ((0 == (xbyte&0xFF)) && y)
{
clocks += AddLine("","TDC"," ; Set DP ",0,2);
clocks += AddLine("","ADC","#$100",0,3);
clocks += AddLine("","TCD"," ; Set DP ",0,2);
}
#endif
if ((xs>=x)&&(xs<(x+width)))
{
if ((dp & 0xFF00) != (xbyte & 0xFF00))
{
int delta = (xbyte&0xFF00) - (dp & 0xFF00);
if (delta < 0)
{
delta--; // need a fudge because of carry
}
clocks += AddLine("", "TDC", " ; Set DP ", 0, 2);
int delta = (xbyte&0xFF00) - (A+C); //(dp & 0xFF00);
A = ADC(A,delta,&C);
clocks += AddLine("","ADC","#%d",delta,3);
clocks += AddLine("","TCD"," ; Set DP ",0,2);
clocks += AddLine("","TCD"," ; Set DP $%04X",A,2);
}
clocks += AddLine("", "PEI", "$%02X", xbyte & 0xFF, 6);
dp = xbyte;
@ -189,13 +199,18 @@ void CompileBlockPEI(RAWDATA *result, int x, int width)
if (y < 7)
{
clocks += AddLine("","TSC"," ;",0,2);
clocks += AddLine("","ADC","#%d",160+(width>>1),3);
clocks += AddLine("","TCS"," ; Set Stack ",0,2);
S+=160;
int delta = S - (A+C);
A = ADC(A,delta,&C);
clocks += AddLine("", "ADC", "#%d", delta, 3);
clocks += AddLine("","TCS"," ; Set S $%04X",A,2);
}
}
clocks += AddLine("","RTL"," ;%d cycles",clocks+6,6);
// clocks += AddLine("","RTL"," ;%d cycles",clocks+6,6);
clocks += AddLine("","JMP","BRET ;%d cycles",clocks+3,3);
}
RAWDATA* CompilePEI()