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gatodecodercolsleft.cpp
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gatodecodercolsleft.cpp
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#include "gatodecodercolsleft.h"
/* This decoder is based on Zorrom's cols-left module.
* Bits start at the upper left, move right, and then
* wrap around to the next row.
*/
GatoDecoderColsLeft::GatoDecoderColsLeft(){
name="cols-left";
}
QByteArray GatoDecoderColsLeft::decode(GatoROM *gr){
uint32_t adr=0;
QByteArray ba;
int wordsize=gr->wordsize;
gr->eval();
//We might be dynamic, but we still don't want to crash.
if(gr->outputcols%wordsize!=0) return ba;
int skip=gr->outputcols/wordsize;
//Each row contains sixteen 8-bit words.
//We calculate that dynamically to be more generic.
for(unsigned int row=0; row<gr->outputrows; row++){
for(int word=(gr->outputcols/wordsize)-1; word>=0; word--){
uint32_t w=0;
for(int bit=wordsize-1; bit>=0; bit--){
GatoBit *B=gr->outputbit(row,bit*skip+word);
assert(B); //If this fails, we're about to crash.
//Update target address and mask.
B->adr=adr;
B->mask=1<<bit;
if(B->getVal())
w|=B->mask;
}
//This is implicitly little endian.
for(int bitcount=wordsize; bitcount>0; bitcount-=8){
ba.append(w&0xFF);
w=w>>8;
adr++;
}
}
}
return ba;
}