Mercurial > repos > blastem

comparison cpu_dsl.py @ 1709:9c058ea77b7a

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Implementation of carry/overflow flags for adc instructions in CPU DSL
author Michael Pavone <pavone@retrodev.com>
date Mon, 28 Jan 2019 22:49:02 -0800
parents 5bfed2eedc9d
children 2344b3650b38
comparison
equal deleted inserted replaced
1708:5bfed2eedc9d 1709:9c058ea77b7a
418 reg = prog.resolveReg(reg, None, (), False) 418 reg = prog.resolveReg(reg, None, (), False)
419 return '({reg} & 1 << {bit})'.format(reg=reg, bit=bit) 419 return '({reg} & 1 << {bit})'.format(reg=reg, bit=bit)
420 else: 420 else:
421 return prog.resolveReg(carryStorage, None, (), False) 421 return prog.resolveReg(carryStorage, None, (), False)
422 422
423 def _adcCImpl(prog, params, rawParams): 423 def _adcCImpl(prog, params, rawParams, flagUpdates):
424 424 needsCarry = needsOflow = needsHalf = False
425 return '\n\t{dst} = {a} + {b} + ({check} ? 1 : 0);'.format(dst = params[2], 425 if flagUpdates:
426 a = params[0], b = params[1], check=_getCarryCheck(prog) 426 for flag in flagUpdates:
427 calc = prog.flags.flagCalc[flag]
428 if calc == 'carry':
429 needsCarry = True
430 elif calc == 'half-carry':
431 needsHalf = True
432 elif calc == 'overflow':
433 needsOflow = True
434 decl = ''
435 carryCheck = _getCarryCheck(prog)
436 if needsCarry or needsOflow or needsHalf:
437 size = prog.paramSize(rawParams[2])
438 if needsCarry:
439 size *= 2
440 decl,name = prog.getTemp(size)
441 dst = prog.carryFlowDst = name
442 prog.lastA = params[0]
443 prog.lastB = '({b} ^ ({check} ? 1 : 0))'.format(b = params[1], check = carryCheck)
444 prog.lastBFlow = prog.lastB
445 else:
446 dst = params[2]
447 return decl + '\n\t{dst} = {a} + {b} + ({check} ? 1 : 0);'.format(dst = dst,
448 a = params[0], b = params[1], check = carryCheck
427 ) 449 )
428 450
429 def _sbcCImpl(prog, params, rawParams): 451 def _sbcCImpl(prog, params, rawParams):
430 return '\n\t{dst} = {a} - {b} - ({check} ? 1 : 0);'.format(dst = params[2], 452 return '\n\t{dst} = {a} - {b} - ({check} ? 1 : 0);'.format(dst = params[2],
431 a = params[0], b = params[1], check=_getCarryCheck(prog) 453 a = params[0], b = params[1], check=_getCarryCheck(prog)