decChk method
void
decChk()
Implementation
void decChk() {
//Debugger.verbose('${pcHex(-1)} [dec_chk]');
final operands = mem.loadb(programCounter- 1) < 193
? visitOperandsLongForm()
: visitOperandsVar(2, false);
final value = MathHelper.toSigned(readVariable(operands[0].rawValue!)) - 1;
//(ref http://www.gnelson.demon.co.uk/zspec/sect14.html notes #5)
writeVariable(operands[0].rawValue!, value);
branch(value < MathHelper.toSigned(operands[1].value!));
}