Reorg 6502 files. Count cycles. Pending extra cycles on page change.

This commit is contained in:
Ivan Izaguirre 2019-02-28 23:54:38 +01:00
parent ac73b8823c
commit 55ad73d01d
7 changed files with 838 additions and 831 deletions

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@ -5,17 +5,15 @@ import "go6502/core6502"
// Run instantiates an apple2 and start emulation
func Run(romFile string, log bool) {
mmu := newAddressSpace(romFile)
var s core6502.State
s.Mem = mmu
s := core6502.NewNMOS6502(mmu)
fe := newAnsiConsoleFrontend(mmu)
mmu.ioPage.setKeyboardProvider(fe)
go fe.textModeGoRoutine()
// Start the processor
core6502.Reset(&s)
s.Reset()
for {
core6502.ExecuteInstruction(&s, log)
s.ExecuteInstruction(log)
}
}

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@ -6,18 +6,15 @@ import (
)
func TestFunctional(t *testing.T) {
m := new(FlatMemory)
s := NewNMOS6502(m)
//t.SkipNow()
var s State
var m FlatMemory
s.Mem = &m
// Test suite from https://github.com/Klaus2m5/6502_65C02_functional_tests
m.loadBinary("testdata/6502_functional_test.bin")
s.Reg.setPC(0x0400)
s.reg.setPC(0x0400)
for true {
testCase := s.Mem.Peek(0x0200)
testCase := s.mem.Peek(0x0200)
if testCase >= 240 {
break
}
@ -25,10 +22,12 @@ func TestFunctional(t *testing.T) {
if log {
fmt.Printf("[ %d ] ", testCase)
}
pc := s.Reg.getPC()
ExecuteInstruction(&s, log)
if pc == s.Reg.getPC() {
pc := s.reg.getPC()
s.ExecuteInstruction(log)
if pc == s.reg.getPC() {
t.Errorf("Failure in test %v.", testCase)
}
}
t.Errorf("Tests complited in %v megacycles.\n", s.cycles/1000000)
}

103
core6502/addressing.go Normal file
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@ -0,0 +1,103 @@
package core6502
const (
modeImplicit = iota + 1
modeImplicitX
modeImplicitY
modeAccumulator
modeImmediate
modeZeroPage
modeZeroPageX
modeZeroPageY
modeRelative
modeAbsolute
modeAbsoluteX
modeAbsoluteY
modeIndirect
modeIndexedIndirectX
modeIndirectIndexedY
)
func getWordInLine(line []uint8) uint16 {
return uint16(line[1]) + 0x100*uint16(line[2])
}
func resolveValue(s *State, line []uint8, opcode opcode) uint8 {
getValue, _, _ := resolve(s, line, opcode)
return getValue()
}
func resolveGetSetValue(s *State, line []uint8, opcode opcode) (value uint8, setValue func(uint8)) {
getValue, setValue, _ := resolve(s, line, opcode)
value = getValue()
return
}
func resolveSetValue(s *State, line []uint8, opcode opcode) func(uint8) {
_, setValue, _ := resolve(s, line, opcode)
return setValue
}
func resolveAddress(s *State, line []uint8, opcode opcode) uint16 {
_, _, address := resolve(s, line, opcode)
return address
}
func resolve(s *State, line []uint8, opcode opcode) (getValue func() uint8, setValue func(uint8), address uint16) {
hasAddress := true
register := regNone
switch opcode.addressMode {
case modeAccumulator:
getValue = func() uint8 { return s.reg.getA() }
hasAddress = false
register = regA
case modeImplicitX:
getValue = func() uint8 { return s.reg.getX() }
hasAddress = false
register = regX
case modeImplicitY:
getValue = func() uint8 { return s.reg.getY() }
hasAddress = false
register = regY
case modeImmediate:
getValue = func() uint8 { return line[1] }
hasAddress = false
case modeZeroPage:
address = uint16(line[1])
case modeZeroPageX:
address = uint16(line[1] + s.reg.getX())
case modeZeroPageY:
address = uint16(line[1] + s.reg.getY())
case modeAbsolute:
address = getWordInLine(line)
case modeAbsoluteX:
address = getWordInLine(line) + uint16(s.reg.getX())
case modeAbsoluteY:
address = getWordInLine(line) + uint16(s.reg.getY())
case modeIndexedIndirectX:
addressAddress := uint8(line[1] + s.reg.getX())
address = getZeroPageWord(s.mem, addressAddress)
case modeIndirect:
addressAddress := getWordInLine(line)
address = getWord(s.mem, addressAddress)
case modeIndirectIndexedY:
address = getZeroPageWord(s.mem, line[1]) +
uint16(s.reg.getY())
}
if hasAddress {
getValue = func() uint8 { return s.mem.Peek(address) }
}
setValue = func(value uint8) {
if hasAddress {
s.mem.Poke(address, value)
} else if register != regNone {
s.reg.setRegister(register, value)
} else {
// Todo: assert impossible
}
}
return
}

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@ -2,124 +2,24 @@ package core6502
import "fmt"
// State represents the state of the simulated device
type State struct {
Reg registers
Mem Memory
}
const (
modeImplicit = iota + 1
modeImplicitX
modeImplicitY
modeAccumulator
modeImmediate
modeZeroPage
modeZeroPageX
modeZeroPageY
modeRelative
modeAbsolute
modeAbsoluteX
modeAbsoluteY
modeIndirect
modeIndexedIndirectX
modeIndirectIndexedY
)
const (
vectorNMI uint16 = 0xfffa
vectorReset uint16 = 0xfffc
vectorBreak uint16 = 0xfffe
)
// https://www.masswerk.at/6502/6502_instruction_set.html
// http://www.emulator101.com/reference/6502-reference.html
// https://www.csh.rit.edu/~moffitt/docs/6502.html#FLAGS
// https://ia800509.us.archive.org/18/items/Programming_the_6502/Programming_the_6502.pdf
func getWordInLine(line []uint8) uint16 {
return uint16(line[1]) + 0x100*uint16(line[2])
// State represents the state of the simulated device
type State struct {
reg registers
mem Memory
cycles int64
opcodes *[256]opcode
}
func resolveValue(s *State, line []uint8, opcode opcode) uint8 {
getValue, _, _ := resolve(s, line, opcode)
return getValue()
}
func resolveGetSetValue(s *State, line []uint8, opcode opcode) (value uint8, setValue func(uint8)) {
getValue, setValue, _ := resolve(s, line, opcode)
value = getValue()
return
}
func resolveSetValue(s *State, line []uint8, opcode opcode) func(uint8) {
_, setValue, _ := resolve(s, line, opcode)
return setValue
}
func resolveAddress(s *State, line []uint8, opcode opcode) uint16 {
_, _, address := resolve(s, line, opcode)
return address
}
func resolve(s *State, line []uint8, opcode opcode) (getValue func() uint8, setValue func(uint8), address uint16) {
hasAddress := true
register := regNone
switch opcode.addressMode {
case modeAccumulator:
getValue = func() uint8 { return s.Reg.getA() }
hasAddress = false
register = regA
case modeImplicitX:
getValue = func() uint8 { return s.Reg.getX() }
hasAddress = false
register = regX
case modeImplicitY:
getValue = func() uint8 { return s.Reg.getY() }
hasAddress = false
register = regY
case modeImmediate:
getValue = func() uint8 { return line[1] }
hasAddress = false
case modeZeroPage:
address = uint16(line[1])
case modeZeroPageX:
address = uint16(line[1] + s.Reg.getX())
case modeZeroPageY:
address = uint16(line[1] + s.Reg.getY())
case modeAbsolute:
address = getWordInLine(line)
case modeAbsoluteX:
address = getWordInLine(line) + uint16(s.Reg.getX())
case modeAbsoluteY:
address = getWordInLine(line) + uint16(s.Reg.getY())
case modeIndexedIndirectX:
addressAddress := uint8(line[1] + s.Reg.getX())
address = getZeroPageWord(s.Mem, addressAddress)
case modeIndirect:
addressAddress := getWordInLine(line)
address = getWord(s.Mem, addressAddress)
case modeIndirectIndexedY:
address = getZeroPageWord(s.Mem, line[1]) +
uint16(s.Reg.getY())
}
if hasAddress {
getValue = func() uint8 { return s.Mem.Peek(address) }
}
setValue = func(value uint8) {
if hasAddress {
s.Mem.Poke(address, value)
} else if register != regNone {
s.Reg.setRegister(register, value)
} else {
// Todo: assert impossible
}
}
return
}
const (
vectorNMI uint16 = 0xfffa
vectorReset uint16 = 0xfffc
vectorBreak uint16 = 0xfffe
)
type opcode struct {
name string
@ -131,424 +31,8 @@ type opcode struct {
type opFunc func(s *State, line []uint8, opcode opcode)
func buildOpTransfer(regSrc int, regDst int) opFunc {
return func(s *State, line []uint8, opcode opcode) {
value := s.Reg.getRegister(regSrc)
s.Reg.setRegister(regDst, value)
if regDst != regSP {
s.Reg.updateFlagZN(value)
}
}
}
func buildOpIncDec(inc bool) opFunc {
return func(s *State, line []uint8, opcode opcode) {
value, setValue := resolveGetSetValue(s, line, opcode)
if inc {
value++
} else {
value--
}
s.Reg.updateFlagZN(value)
setValue(value)
}
}
func buildOpShift(isLeft bool, isRotate bool) opFunc {
return func(s *State, line []uint8, opcode opcode) {
value, setValue := resolveGetSetValue(s, line, opcode)
oldCarry := s.Reg.getFlagBit(flagC)
var carry bool
if isLeft {
carry = (value & 0x80) != 0
value <<= 1
if isRotate {
value += oldCarry
}
} else {
carry = (value & 0x01) != 0
value >>= 1
if isRotate {
value += oldCarry << 7
}
}
s.Reg.updateFlag(flagC, carry)
s.Reg.updateFlagZN(value)
setValue(value)
}
}
func buildOpLoad(regDst int) opFunc {
return func(s *State, line []uint8, opcode opcode) {
value := resolveValue(s, line, opcode)
s.Reg.setRegister(regDst, value)
s.Reg.updateFlagZN(value)
}
}
func buildOpStore(regSrc int) opFunc {
return func(s *State, line []uint8, opcode opcode) {
setValue := resolveSetValue(s, line, opcode)
value := s.Reg.getRegister(regSrc)
setValue(value)
}
}
func buildOpUpdateFlag(flag uint8, value bool) opFunc {
return func(s *State, line []uint8, opcode opcode) {
s.Reg.updateFlag(flag, value)
}
}
func buildOpBranch(flag uint8, value bool) opFunc {
return func(s *State, line []uint8, opcode opcode) {
if s.Reg.getFlag(flag) == value {
// This assumes that PC is already pointing to the next instruction
pc := s.Reg.getPC()
pc += uint16(int8(line[1]))
s.Reg.setPC(pc)
}
}
}
func opBIT(s *State, line []uint8, opcode opcode) {
value := resolveValue(s, line, opcode)
acc := s.Reg.getA()
// Future note: The immediate addressing mode (65C02 or 65816 only) does not affect V.
s.Reg.updateFlag(flagZ, value&acc == 0)
s.Reg.updateFlag(flagN, value&(1<<7) != 0)
s.Reg.updateFlag(flagV, value&(1<<6) != 0)
}
func buildOpCompare(reg int) opFunc {
return func(s *State, line []uint8, opcode opcode) {
value := resolveValue(s, line, opcode)
reference := s.Reg.getRegister(reg)
s.Reg.updateFlagZN(reference - value)
s.Reg.updateFlag(flagC, reference >= value)
}
}
func operationAnd(a uint8, b uint8) uint8 { return a & b }
func operationOr(a uint8, b uint8) uint8 { return a | b }
func operationXor(a uint8, b uint8) uint8 { return a ^ b }
func buildOpLogic(operation func(uint8, uint8) uint8) opFunc {
return func(s *State, line []uint8, opcode opcode) {
value := resolveValue(s, line, opcode)
result := operation(value, s.Reg.getA())
s.Reg.setA(result)
s.Reg.updateFlagZN(result)
}
}
func opADC(s *State, line []uint8, opcode opcode) {
value := resolveValue(s, line, opcode)
aValue := s.Reg.getA()
carry := s.Reg.getFlagBit(flagC)
total := uint16(aValue) + uint16(value) + uint16(carry)
signedTotal := int16(int8(aValue)) + int16(int8(value)) + int16(carry)
truncated := uint8(total)
if s.Reg.getFlag(flagD) {
totalBcdLo := int(aValue&0x0f) + int(value&0x0f) + int(carry)
totalBcdHi := int(aValue>>4) + int(value>>4)
if totalBcdLo >= 10 {
totalBcdHi++
}
totalBcd := (totalBcdHi%10)<<4 + (totalBcdLo % 10)
s.Reg.setA(uint8(totalBcd))
s.Reg.updateFlag(flagC, totalBcdHi > 9)
} else {
s.Reg.setA(truncated)
s.Reg.updateFlag(flagC, total > 0xFF)
}
// ZNV flags behave for BCD as if the operation was binary?
s.Reg.updateFlagZN(truncated)
s.Reg.updateFlag(flagV, signedTotal < -128 || signedTotal > 127)
}
func opSBC(s *State, line []uint8, opcode opcode) {
value := resolveValue(s, line, opcode)
aValue := s.Reg.getA()
carry := s.Reg.getFlagBit(flagC)
total := 0x100 + uint16(aValue) - uint16(value) + uint16(carry) - 1
signedTotal := int16(int8(aValue)) - int16(int8(value)) + int16(carry) - 1
truncated := uint8(total)
if s.Reg.getFlag(flagD) {
totalBcdLo := 10 + int(aValue&0x0f) - int(value&0x0f) + int(carry) - 1
totalBcdHi := 10 + int(aValue>>4) - int(value>>4)
if totalBcdLo < 10 {
totalBcdHi--
}
totalBcd := (totalBcdHi%10)<<4 + (totalBcdLo % 10)
s.Reg.setA(uint8(totalBcd))
s.Reg.updateFlag(flagC, totalBcdHi >= 10)
} else {
s.Reg.setA(truncated)
s.Reg.updateFlag(flagC, total > 0xFF)
}
// ZNV flags behave for SBC as if the operation was binary
s.Reg.updateFlagZN(truncated)
s.Reg.updateFlag(flagV, signedTotal < -128 || signedTotal > 127)
}
const stackAddress uint16 = 0x0100
func pushByte(s *State, value uint8) {
adresss := stackAddress + uint16(s.Reg.getSP())
s.Mem.Poke(adresss, value)
s.Reg.setSP(s.Reg.getSP() - 1)
}
func pullByte(s *State) uint8 {
s.Reg.setSP(s.Reg.getSP() + 1)
adresss := stackAddress + uint16(s.Reg.getSP())
return s.Mem.Peek(adresss)
}
func pushWord(s *State, value uint16) {
pushByte(s, uint8(value>>8))
pushByte(s, uint8(value))
}
func pullWord(s *State) uint16 {
return uint16(pullByte(s)) +
(uint16(pullByte(s)) << 8)
}
func opPLA(s *State, line []uint8, opcode opcode) {
value := pullByte(s)
s.Reg.setA(value)
s.Reg.updateFlagZN(value)
}
func opPLP(s *State, line []uint8, opcode opcode) {
value := pullByte(s)
s.Reg.setP(value)
}
func opPHA(s *State, line []uint8, opcode opcode) {
pushByte(s, s.Reg.getA())
}
func opPHP(s *State, line []uint8, opcode opcode) {
pushByte(s, s.Reg.getP()|(flagB+flag5))
}
func opJMP(s *State, line []uint8, opcode opcode) {
address := resolveAddress(s, line, opcode)
s.Reg.setPC(address)
}
func opNOP(s *State, line []uint8, opcode opcode) {}
func opJSR(s *State, line []uint8, opcode opcode) {
pushWord(s, s.Reg.getPC()-1)
address := resolveAddress(s, line, opcode)
s.Reg.setPC(address)
}
func opRTI(s *State, line []uint8, opcode opcode) {
s.Reg.setP(pullByte(s))
s.Reg.setPC(pullWord(s))
}
func opRTS(s *State, line []uint8, opcode opcode) {
s.Reg.setPC(pullWord(s) + 1)
}
func opBRK(s *State, line []uint8, opcode opcode) {
pushWord(s, s.Reg.getPC()+1)
pushByte(s, s.Reg.getP()|(flagB+flag5))
s.Reg.setFlag(flagI)
s.Reg.setPC(getWord(s.Mem, vectorBreak))
}
var opcodes = [256]opcode{
0x00: opcode{"BRK", 1, 7, modeImplicit, opBRK},
0x4C: opcode{"JMP", 3, 3, modeAbsolute, opJMP},
0x6C: opcode{"JMP", 3, 3, modeIndirect, opJMP},
0x20: opcode{"JSR", 3, 6, modeAbsolute, opJSR},
0x40: opcode{"RTI", 1, 6, modeImplicit, opRTI},
0x60: opcode{"RTS", 1, 6, modeImplicit, opRTS},
0x48: opcode{"PHA", 1, 3, modeImplicit, opPHA},
0x08: opcode{"PHP", 1, 3, modeImplicit, opPHP},
0x68: opcode{"PLA", 1, 4, modeImplicit, opPLA},
0x28: opcode{"PLP", 1, 4, modeImplicit, opPLP},
0x09: opcode{"ORA", 2, 2, modeImmediate, buildOpLogic(operationOr)},
0x05: opcode{"ORA", 2, 3, modeZeroPage, buildOpLogic(operationOr)},
0x15: opcode{"ORA", 2, 4, modeZeroPageX, buildOpLogic(operationOr)},
0x0D: opcode{"ORA", 3, 4, modeAbsolute, buildOpLogic(operationOr)},
0x1D: opcode{"ORA", 3, 4, modeAbsoluteX, buildOpLogic(operationOr)}, // Extra cycles
0x19: opcode{"ORA", 3, 4, modeAbsoluteY, buildOpLogic(operationOr)}, // Extra cycles
0x01: opcode{"ORA", 2, 6, modeIndexedIndirectX, buildOpLogic(operationOr)},
0x11: opcode{"ORA", 2, 5, modeIndirectIndexedY, buildOpLogic(operationOr)}, // Extra cycles
0x29: opcode{"AND", 2, 2, modeImmediate, buildOpLogic(operationAnd)},
0x25: opcode{"AND", 2, 3, modeZeroPage, buildOpLogic(operationAnd)},
0x35: opcode{"AND", 2, 4, modeZeroPageX, buildOpLogic(operationAnd)},
0x2D: opcode{"AND", 3, 4, modeAbsolute, buildOpLogic(operationAnd)},
0x3D: opcode{"AND", 3, 4, modeAbsoluteX, buildOpLogic(operationAnd)}, // Extra cycles
0x39: opcode{"AND", 3, 4, modeAbsoluteY, buildOpLogic(operationAnd)}, // Extra cycles
0x21: opcode{"AND", 2, 6, modeIndexedIndirectX, buildOpLogic(operationAnd)},
0x31: opcode{"AND", 2, 5, modeIndirectIndexedY, buildOpLogic(operationAnd)}, // Extra cycles
0x49: opcode{"EOR", 2, 2, modeImmediate, buildOpLogic(operationXor)},
0x45: opcode{"EOR", 2, 3, modeZeroPage, buildOpLogic(operationXor)},
0x55: opcode{"EOR", 2, 4, modeZeroPageX, buildOpLogic(operationXor)},
0x4D: opcode{"EOR", 3, 4, modeAbsolute, buildOpLogic(operationXor)},
0x5D: opcode{"EOR", 3, 4, modeAbsoluteX, buildOpLogic(operationXor)}, // Extra cycles
0x59: opcode{"EOR", 3, 4, modeAbsoluteY, buildOpLogic(operationXor)}, // Extra cycles
0x41: opcode{"EOR", 2, 6, modeIndexedIndirectX, buildOpLogic(operationXor)},
0x51: opcode{"EOR", 2, 5, modeIndirectIndexedY, buildOpLogic(operationXor)}, // Extra cycles
0x69: opcode{"ADC", 2, 2, modeImmediate, opADC},
0x65: opcode{"ADC", 2, 3, modeZeroPage, opADC},
0x75: opcode{"ADC", 2, 4, modeZeroPageX, opADC},
0x6D: opcode{"ADC", 3, 4, modeAbsolute, opADC},
0x7D: opcode{"ADC", 3, 4, modeAbsoluteX, opADC}, // Extra cycles
0x79: opcode{"ADC", 3, 4, modeAbsoluteY, opADC}, // Extra cycles
0x61: opcode{"ADC", 2, 6, modeIndexedIndirectX, opADC},
0x71: opcode{"ADC", 2, 5, modeIndirectIndexedY, opADC}, // Extra cycles
0xE9: opcode{"SBC", 2, 2, modeImmediate, opSBC},
0xE5: opcode{"SBC", 2, 3, modeZeroPage, opSBC},
0xF5: opcode{"SBC", 2, 4, modeZeroPageX, opSBC},
0xED: opcode{"SBC", 3, 4, modeAbsolute, opSBC},
0xFD: opcode{"SBC", 3, 4, modeAbsoluteX, opSBC}, // Extra cycles
0xF9: opcode{"SBC", 3, 4, modeAbsoluteY, opSBC}, // Extra cycles
0xE1: opcode{"SBC", 2, 6, modeIndexedIndirectX, opSBC},
0xF1: opcode{"SBC", 2, 5, modeIndirectIndexedY, opSBC}, // Extra cycles
0x24: opcode{"BIT", 2, 3, modeZeroPage, opBIT},
0x2C: opcode{"BIT", 3, 3, modeAbsolute, opBIT},
0xC9: opcode{"CMP", 2, 2, modeImmediate, buildOpCompare(regA)},
0xC5: opcode{"CMP", 2, 3, modeZeroPage, buildOpCompare(regA)},
0xD5: opcode{"CMP", 2, 4, modeZeroPageX, buildOpCompare(regA)},
0xCD: opcode{"CMP", 3, 4, modeAbsolute, buildOpCompare(regA)},
0xDD: opcode{"CMP", 3, 4, modeAbsoluteX, buildOpCompare(regA)}, // Extra cycles
0xD9: opcode{"CMP", 3, 4, modeAbsoluteY, buildOpCompare(regA)}, // Extra cycles
0xC1: opcode{"CMP", 2, 6, modeIndexedIndirectX, buildOpCompare(regA)},
0xD1: opcode{"CMP", 2, 5, modeIndirectIndexedY, buildOpCompare(regA)}, // Extra cycles
0xE0: opcode{"CPX", 2, 2, modeImmediate, buildOpCompare(regX)},
0xE4: opcode{"CPX", 2, 3, modeZeroPage, buildOpCompare(regX)},
0xEC: opcode{"CPX", 3, 4, modeAbsolute, buildOpCompare(regX)},
0xC0: opcode{"CPY", 2, 2, modeImmediate, buildOpCompare(regY)},
0xC4: opcode{"CPY", 2, 3, modeZeroPage, buildOpCompare(regY)},
0xCC: opcode{"CPY", 3, 4, modeAbsolute, buildOpCompare(regY)},
0x2A: opcode{"ROL", 1, 2, modeAccumulator, buildOpShift(true, true)},
0x26: opcode{"ROL", 2, 5, modeZeroPage, buildOpShift(true, true)},
0x36: opcode{"ROL", 2, 6, modeZeroPageX, buildOpShift(true, true)},
0x2E: opcode{"ROL", 3, 6, modeAbsolute, buildOpShift(true, true)},
0x3E: opcode{"ROL", 3, 7, modeAbsoluteX, buildOpShift(true, true)},
0x6A: opcode{"ROR", 1, 2, modeAccumulator, buildOpShift(false, true)},
0x66: opcode{"ROR", 2, 5, modeZeroPage, buildOpShift(false, true)},
0x76: opcode{"ROR", 2, 6, modeZeroPageX, buildOpShift(false, true)},
0x6E: opcode{"ROR", 3, 6, modeAbsolute, buildOpShift(false, true)},
0x7E: opcode{"ROR", 3, 7, modeAbsoluteX, buildOpShift(false, true)},
0x0A: opcode{"ASL", 1, 2, modeAccumulator, buildOpShift(true, false)},
0x06: opcode{"ASL", 2, 5, modeZeroPage, buildOpShift(true, false)},
0x16: opcode{"ASL", 2, 6, modeZeroPageX, buildOpShift(true, false)},
0x0E: opcode{"ASL", 3, 6, modeAbsolute, buildOpShift(true, false)},
0x1E: opcode{"ASL", 3, 7, modeAbsoluteX, buildOpShift(true, false)},
0x4A: opcode{"LSR", 1, 2, modeAccumulator, buildOpShift(false, false)},
0x46: opcode{"LSR", 2, 5, modeZeroPage, buildOpShift(false, false)},
0x56: opcode{"LSR", 2, 6, modeZeroPageX, buildOpShift(false, false)},
0x4E: opcode{"LSR", 3, 6, modeAbsolute, buildOpShift(false, false)},
0x5E: opcode{"LSR", 3, 7, modeAbsoluteX, buildOpShift(false, false)},
0x38: opcode{"SEC", 1, 2, modeImplicit, buildOpUpdateFlag(flagC, true)},
0xF8: opcode{"SED", 1, 2, modeImplicit, buildOpUpdateFlag(flagD, true)},
0x78: opcode{"SEI", 1, 2, modeImplicit, buildOpUpdateFlag(flagI, true)},
0x18: opcode{"CLC", 1, 2, modeImplicit, buildOpUpdateFlag(flagC, false)},
0xD8: opcode{"CLD", 1, 2, modeImplicit, buildOpUpdateFlag(flagD, false)},
0x58: opcode{"CLI", 1, 2, modeImplicit, buildOpUpdateFlag(flagI, false)},
0xB8: opcode{"CLV", 1, 2, modeImplicit, buildOpUpdateFlag(flagV, false)},
0xE6: opcode{"INC", 2, 5, modeZeroPage, buildOpIncDec(true)},
0xF6: opcode{"INC", 2, 6, modeZeroPageX, buildOpIncDec(true)},
0xEE: opcode{"INC", 3, 6, modeAbsolute, buildOpIncDec(true)},
0xFE: opcode{"INC", 3, 7, modeAbsoluteX, buildOpIncDec(true)},
0xC6: opcode{"DEC", 2, 5, modeZeroPage, buildOpIncDec(false)},
0xD6: opcode{"DEC", 2, 6, modeZeroPageX, buildOpIncDec(false)},
0xCE: opcode{"DEC", 3, 6, modeAbsolute, buildOpIncDec(false)},
0xDE: opcode{"DEC", 3, 7, modeAbsoluteX, buildOpIncDec(false)},
0xE8: opcode{"INX", 1, 2, modeImplicitX, buildOpIncDec(true)},
0xC8: opcode{"INY", 1, 2, modeImplicitY, buildOpIncDec(true)},
0xCA: opcode{"DEX", 1, 2, modeImplicitX, buildOpIncDec(false)},
0x88: opcode{"DEY", 1, 2, modeImplicitY, buildOpIncDec(false)},
0xAA: opcode{"TAX", 1, 2, modeImplicit, buildOpTransfer(regA, regX)},
0xA8: opcode{"TAY", 1, 2, modeImplicit, buildOpTransfer(regA, regY)},
0x8A: opcode{"TXA", 1, 2, modeImplicit, buildOpTransfer(regX, regA)},
0x98: opcode{"TYA", 1, 2, modeImplicit, buildOpTransfer(regY, regA)},
0x9A: opcode{"TXS", 1, 2, modeImplicit, buildOpTransfer(regX, regSP)},
0xBA: opcode{"TSX", 1, 2, modeImplicit, buildOpTransfer(regSP, regX)},
0xA9: opcode{"LDA", 2, 2, modeImmediate, buildOpLoad(regA)},
0xA5: opcode{"LDA", 2, 3, modeZeroPage, buildOpLoad(regA)},
0xB5: opcode{"LDA", 2, 4, modeZeroPageX, buildOpLoad(regA)},
0xAD: opcode{"LDA", 3, 4, modeAbsolute, buildOpLoad(regA)},
0xBD: opcode{"LDA", 3, 4, modeAbsoluteX, buildOpLoad(regA)}, // Extra cycles
0xB9: opcode{"LDA", 3, 4, modeAbsoluteY, buildOpLoad(regA)}, // Extra cycles
0xA1: opcode{"LDA", 2, 6, modeIndexedIndirectX, buildOpLoad(regA)},
0xB1: opcode{"LDA", 2, 5, modeIndirectIndexedY, buildOpLoad(regA)}, // Extra cycles
0xA2: opcode{"LDX", 2, 2, modeImmediate, buildOpLoad(regX)},
0xA6: opcode{"LDX", 2, 3, modeZeroPage, buildOpLoad(regX)},
0xB6: opcode{"LDX", 2, 4, modeZeroPageY, buildOpLoad(regX)},
0xAE: opcode{"LDX", 3, 4, modeAbsolute, buildOpLoad(regX)},
0xBE: opcode{"LDX", 3, 4, modeAbsoluteY, buildOpLoad(regX)}, // Extra cycles
0xA0: opcode{"LDY", 2, 2, modeImmediate, buildOpLoad(regY)},
0xA4: opcode{"LDY", 2, 3, modeZeroPage, buildOpLoad(regY)},
0xB4: opcode{"LDY", 2, 4, modeZeroPageX, buildOpLoad(regY)},
0xAC: opcode{"LDY", 3, 4, modeAbsolute, buildOpLoad(regY)},
0xBC: opcode{"LDY", 3, 4, modeAbsoluteX, buildOpLoad(regY)}, // Extra cycles
0x85: opcode{"STA", 2, 3, modeZeroPage, buildOpStore(regA)},
0x95: opcode{"STA", 2, 4, modeZeroPageX, buildOpStore(regA)},
0x8D: opcode{"STA", 3, 4, modeAbsolute, buildOpStore(regA)},
0x9D: opcode{"STA", 3, 5, modeAbsoluteX, buildOpStore(regA)},
0x99: opcode{"STA", 3, 5, modeAbsoluteY, buildOpStore(regA)},
0x81: opcode{"STA", 2, 6, modeIndexedIndirectX, buildOpStore(regA)},
0x91: opcode{"STA", 2, 6, modeIndirectIndexedY, buildOpStore(regA)},
0x86: opcode{"STX", 2, 3, modeZeroPage, buildOpStore(regX)},
0x96: opcode{"STX", 2, 4, modeZeroPageY, buildOpStore(regX)},
0x8E: opcode{"STX", 3, 4, modeAbsolute, buildOpStore(regX)},
0x84: opcode{"STY", 2, 3, modeZeroPage, buildOpStore(regY)},
0x94: opcode{"STY", 2, 4, modeZeroPageX, buildOpStore(regY)},
0x8C: opcode{"STY", 3, 4, modeAbsolute, buildOpStore(regY)},
0x90: opcode{"BCC", 2, 2, modeRelative, buildOpBranch(flagC, false)}, // Extra cycles
0xB0: opcode{"BCS", 2, 2, modeRelative, buildOpBranch(flagC, true)}, // Extra cycles
0xD0: opcode{"BNE", 2, 2, modeRelative, buildOpBranch(flagZ, false)}, // Extra cycles
0xF0: opcode{"BEQ", 2, 2, modeRelative, buildOpBranch(flagZ, true)}, // Extra cycles
0x10: opcode{"BPL", 2, 2, modeRelative, buildOpBranch(flagN, false)}, // Extra cycles
0x30: opcode{"BMI", 2, 2, modeRelative, buildOpBranch(flagN, true)}, // Extra cycles
0x50: opcode{"BVC", 2, 2, modeRelative, buildOpBranch(flagV, false)}, // Extra cycles
0x70: opcode{"BVS", 2, 2, modeRelative, buildOpBranch(flagV, true)}, // Extra cycles
0xEA: opcode{"NOP", 1, 2, modeImplicit, opNOP},
}
func executeLine(s *State, line []uint8) {
opcode := opcodes[line[0]]
func (s *State) executeLine(line []uint8) {
opcode := s.opcodes[line[0]]
if opcode.cycles == 0 {
panic(fmt.Sprintf("Unknown opcode 0x%02x\n", line[0]))
}
@ -556,10 +40,10 @@ func executeLine(s *State, line []uint8) {
}
// ExecuteInstruction transforms the state given after a single instruction is executed.
func ExecuteInstruction(s *State, log bool) {
pc := s.Reg.getPC()
opcodeID := s.Mem.Peek(pc)
opcode := opcodes[opcodeID]
func (s *State) ExecuteInstruction(log bool) {
pc := s.reg.getPC()
opcodeID := s.mem.Peek(pc)
opcode := s.opcodes[opcodeID]
if opcode.cycles == 0 {
panic(fmt.Sprintf("Unknown opcode 0x%02x\n", opcodeID))
@ -567,27 +51,28 @@ func ExecuteInstruction(s *State, log bool) {
line := make([]uint8, opcode.bytes)
for i := uint8(0); i < opcode.bytes; i++ {
line[i] = s.Mem.Peek(pc)
line[i] = s.mem.Peek(pc)
pc++
}
s.Reg.setPC(pc)
s.reg.setPC(pc)
if log {
fmt.Printf("%#04x %-12s: ", pc, lineString(s, line, opcode))
fmt.Printf("%#04x %-12s: ", pc, lineString(line, opcode))
}
opcode.action(s, line, opcode)
s.cycles += int64(opcode.cycles)
if log {
fmt.Printf("%v, [%02x]\n", s.Reg, line)
fmt.Printf("%v, [%02x]\n", s.reg, line)
}
}
// Reset resets the processor state. Moves the program counter to the vector in 0cfffc.
func Reset(s *State) {
startAddress := getWord(s.Mem, vectorReset)
s.Reg.setPC(startAddress)
func (s *State) Reset() {
startAddress := getWord(s.mem, vectorReset)
s.reg.setPC(startAddress)
}
func lineString(s *State, line []uint8, opcode opcode) string {
func lineString(line []uint8, opcode opcode) string {
t := opcode.name
switch opcode.addressMode {
case modeImplicit:

View File

@ -5,486 +5,482 @@ import (
)
func TestLoad(t *testing.T) {
var s State
s.Mem = new(FlatMemory)
s := NewNMOS6502(new(FlatMemory))
executeLine(&s, []uint8{0xA9, 0x42})
if s.Reg.getA() != 0x42 {
s.executeLine([]uint8{0xA9, 0x42})
if s.reg.getA() != 0x42 {
t.Error("Error in LDA #")
}
executeLine(&s, []uint8{0xA9, 0x00})
if s.Reg.getP() != flagZ {
s.executeLine([]uint8{0xA9, 0x00})
if s.reg.getP() != flagZ {
t.Error("Error in flags for LDA $0")
}
executeLine(&s, []uint8{0xA9, 0xF0})
if s.Reg.getP() != flagN {
s.executeLine([]uint8{0xA9, 0xF0})
if s.reg.getP() != flagN {
t.Error("Error in flags for LDA $F0")
}
executeLine(&s, []uint8{0xA0, 0xFE})
if s.Reg.getY() != 0xFE {
s.executeLine([]uint8{0xA0, 0xFE})
if s.reg.getY() != 0xFE {
t.Error("Error in LDY #")
}
s.Mem.Poke(0x38, 0x87)
executeLine(&s, []uint8{0xA5, 0x38})
if s.Reg.getA() != 0x87 {
s.mem.Poke(0x38, 0x87)
s.executeLine([]uint8{0xA5, 0x38})
if s.reg.getA() != 0x87 {
t.Error("Error in LDA zpg")
}
s.Mem.Poke(0x57, 0x90)
s.Reg.setX(0x10)
executeLine(&s, []uint8{0xB5, 0x47})
if s.Reg.getA() != 0x90 {
s.mem.Poke(0x57, 0x90)
s.reg.setX(0x10)
s.executeLine([]uint8{0xB5, 0x47})
if s.reg.getA() != 0x90 {
t.Error("Error in LDA zpg, X")
}
s.Mem.Poke(0x38, 0x12)
s.Reg.setX(0x89)
executeLine(&s, []uint8{0xB5, 0xAF})
if s.Reg.getA() != 0x12 {
s.mem.Poke(0x38, 0x12)
s.reg.setX(0x89)
s.executeLine([]uint8{0xB5, 0xAF})
if s.reg.getA() != 0x12 {
t.Error("Error in LDA zpgX with sero page overflow")
}
s.Mem.Poke(0x1234, 0x67)
executeLine(&s, []uint8{0xAD, 0x34, 0x12})
if s.Reg.getA() != 0x67 {
s.mem.Poke(0x1234, 0x67)
s.executeLine([]uint8{0xAD, 0x34, 0x12})
if s.reg.getA() != 0x67 {
t.Error("Error in LDA abs")
}
s.Mem.Poke(0xC057, 0x7E)
s.Reg.setX(0x57)
executeLine(&s, []uint8{0xBD, 0x00, 0xC0})
if s.Reg.getA() != 0x7E {
s.mem.Poke(0xC057, 0x7E)
s.reg.setX(0x57)
s.executeLine([]uint8{0xBD, 0x00, 0xC0})
if s.reg.getA() != 0x7E {
t.Error("Error in LDA abs, X")
}
s.Mem.Poke(0xD059, 0x7A)
s.Reg.setY(0x59)
executeLine(&s, []uint8{0xB9, 0x00, 0xD0})
if s.Reg.getA() != 0x7A {
s.mem.Poke(0xD059, 0x7A)
s.reg.setY(0x59)
s.executeLine([]uint8{0xB9, 0x00, 0xD0})
if s.reg.getA() != 0x7A {
t.Error("Error in LDA abs, Y")
}
s.Mem.Poke(0x24, 0x74)
s.Mem.Poke(0x25, 0x20)
s.Reg.setX(0x04)
s.Mem.Poke(0x2074, 0x66)
executeLine(&s, []uint8{0xA1, 0x20})
if s.Reg.getA() != 0x66 {
s.mem.Poke(0x24, 0x74)
s.mem.Poke(0x25, 0x20)
s.reg.setX(0x04)
s.mem.Poke(0x2074, 0x66)
s.executeLine([]uint8{0xA1, 0x20})
if s.reg.getA() != 0x66 {
t.Error("Error in LDA (oper,X)")
}
s.Mem.Poke(0x86, 0x28)
s.Mem.Poke(0x87, 0x40)
s.Reg.setY(0x10)
s.Mem.Poke(0x4038, 0x99)
executeLine(&s, []uint8{0xB1, 0x86})
if s.Reg.getA() != 0x99 {
s.mem.Poke(0x86, 0x28)
s.mem.Poke(0x87, 0x40)
s.reg.setY(0x10)
s.mem.Poke(0x4038, 0x99)
s.executeLine([]uint8{0xB1, 0x86})
if s.reg.getA() != 0x99 {
t.Error("Error in LDA (oper),Y")
}
}
func TestStore(t *testing.T) {
var s State
s.Mem = new(FlatMemory)
s.Reg.setA(0x10)
s.Reg.setX(0x40)
s.Reg.setY(0x80)
s := NewNMOS6502(new(FlatMemory))
s.reg.setA(0x10)
s.reg.setX(0x40)
s.reg.setY(0x80)
executeLine(&s, []uint8{0x85, 0x50})
if s.Mem.Peek(0x0050) != 0x10 {
s.executeLine([]uint8{0x85, 0x50})
if s.mem.Peek(0x0050) != 0x10 {
t.Error("Error in STA zpg")
}
executeLine(&s, []uint8{0x86, 0x51})
if s.Mem.Peek(0x0051) != 0x40 {
s.executeLine([]uint8{0x86, 0x51})
if s.mem.Peek(0x0051) != 0x40 {
t.Error("Error in STX zpg")
}
executeLine(&s, []uint8{0x84, 0x52})
if s.Mem.Peek(0x0052) != 0x80 {
s.executeLine([]uint8{0x84, 0x52})
if s.mem.Peek(0x0052) != 0x80 {
t.Error("Error in STY zpg")
}
executeLine(&s, []uint8{0x8D, 0x20, 0xC0})
if s.Mem.Peek(0xC020) != 0x10 {
s.executeLine([]uint8{0x8D, 0x20, 0xC0})
if s.mem.Peek(0xC020) != 0x10 {
t.Error("Error in STA abs")
}
executeLine(&s, []uint8{0x9D, 0x08, 0x10})
if s.Mem.Peek(0x1048) != 0x10 {
s.executeLine([]uint8{0x9D, 0x08, 0x10})
if s.mem.Peek(0x1048) != 0x10 {
t.Error("Error in STA abs, X")
}
}
func TestTransfer(t *testing.T) {
var s State
s := NewNMOS6502(new(FlatMemory))
s.Reg.setA(0xB0)
executeLine(&s, []uint8{0xAA})
if s.Reg.getX() != 0xB0 {
s.reg.setA(0xB0)
s.executeLine([]uint8{0xAA})
if s.reg.getX() != 0xB0 {
t.Error("Error in TAX")
}
if s.Reg.getP() != flagN {
if s.reg.getP() != flagN {
t.Error("Error in TAX flags")
}
s.Reg.setA(0xB1)
executeLine(&s, []uint8{0xA8})
if s.Reg.getY() != 0xB1 {
s.reg.setA(0xB1)
s.executeLine([]uint8{0xA8})
if s.reg.getY() != 0xB1 {
t.Error("Error in TAY")
}
s.Reg.setSP(0xB2)
executeLine(&s, []uint8{0xBA})
if s.Reg.getX() != 0xB2 {
s.reg.setSP(0xB2)
s.executeLine([]uint8{0xBA})
if s.reg.getX() != 0xB2 {
t.Error("Error in TSX")
}
s.Reg.setX(0xB3)
executeLine(&s, []uint8{0x8A})
if s.Reg.getA() != 0xB3 {
s.reg.setX(0xB3)
s.executeLine([]uint8{0x8A})
if s.reg.getA() != 0xB3 {
t.Error("Error in TXA")
}
s.Reg.setX(0xB4)
executeLine(&s, []uint8{0x9A})
if s.Reg.getSP() != 0xB4 {
s.reg.setX(0xB4)
s.executeLine([]uint8{0x9A})
if s.reg.getSP() != 0xB4 {
t.Error("Error in TXS")
}
s.Reg.setY(0xB5)
executeLine(&s, []uint8{0x98})
if s.Reg.getA() != 0xB5 {
s.reg.setY(0xB5)
s.executeLine([]uint8{0x98})
if s.reg.getA() != 0xB5 {
t.Error("Error in TYA")
}
}
func TestIncDec(t *testing.T) {
var s State
s := NewNMOS6502(new(FlatMemory))
s.Reg.setX(0x7E)
executeLine(&s, []uint8{0xE8})
if s.Reg.getX() != 0x7F {
s.reg.setX(0x7E)
s.executeLine([]uint8{0xE8})
if s.reg.getX() != 0x7F {
t.Errorf("Error in INX")
}
s.Reg.setY(0xFC)
executeLine(&s, []uint8{0x88})
if s.Reg.getY() != 0xFB {
s.reg.setY(0xFC)
s.executeLine([]uint8{0x88})
if s.reg.getY() != 0xFB {
t.Error("Error in DEY")
}
if s.Reg.getP() != flagN {
if s.reg.getP() != flagN {
t.Error("Error in DEY flags")
}
}
func TestShiftRotate(t *testing.T) {
var s State
s := NewNMOS6502(new(FlatMemory))
s.Reg.setA(0xF0)
executeLine(&s, []uint8{0x2A})
if s.Reg.getA() != 0xE0 {
s.reg.setA(0xF0)
s.executeLine([]uint8{0x2A})
if s.reg.getA() != 0xE0 {
t.Errorf("Error in ROL")
}
if !s.Reg.getFlag(flagC) {
t.Errorf("Error in ROL carry. %v", s.Reg)
if !s.reg.getFlag(flagC) {
t.Errorf("Error in ROL carry. %v", s.reg)
}
s.Reg.setFlag(flagC)
s.Reg.setA(0x0F)
executeLine(&s, []uint8{0x6A})
if s.Reg.getA() != 0x87 {
t.Errorf("Error in ROR. %v", s.Reg)
s.reg.setFlag(flagC)
s.reg.setA(0x0F)
s.executeLine([]uint8{0x6A})
if s.reg.getA() != 0x87 {
t.Errorf("Error in ROR. %v", s.reg)
}
if !s.Reg.getFlag(flagC) {
if !s.reg.getFlag(flagC) {
t.Errorf("Error in ROR carry")
}
s.Reg.setFlag(flagC)
s.Reg.setA(0x81)
executeLine(&s, []uint8{0x0A})
if s.Reg.getA() != 0x02 {
t.Errorf("Error in ASL. %v", s.Reg)
s.reg.setFlag(flagC)
s.reg.setA(0x81)
s.executeLine([]uint8{0x0A})
if s.reg.getA() != 0x02 {
t.Errorf("Error in ASL. %v", s.reg)
}
if !s.Reg.getFlag(flagC) {
if !s.reg.getFlag(flagC) {
t.Errorf("Error in ASL carry")
}
s.Reg.setFlag(flagC)
s.Reg.setA(0x02)
executeLine(&s, []uint8{0x4A})
if s.Reg.getA() != 0x01 {
t.Errorf("Error in LSR. %v", s.Reg)
s.reg.setFlag(flagC)
s.reg.setA(0x02)
s.executeLine([]uint8{0x4A})
if s.reg.getA() != 0x01 {
t.Errorf("Error in LSR. %v", s.reg)
}
if s.Reg.getFlag(flagC) {
if s.reg.getFlag(flagC) {
t.Errorf("Error in LSR carry")
}
}
func TestClearSetFlag(t *testing.T) {
var s State
s.Reg.setP(0x00)
s := NewNMOS6502(new(FlatMemory))
s.reg.setP(0x00)
executeLine(&s, []uint8{0xF8})
if !s.Reg.getFlag(flagD) {
t.Errorf("Error in SED. %v", s.Reg)
s.executeLine([]uint8{0xF8})
if !s.reg.getFlag(flagD) {
t.Errorf("Error in SED. %v", s.reg)
}
executeLine(&s, []uint8{0xD8})
if s.Reg.getFlag(flagD) {
t.Errorf("Error in CLD. %v", s.Reg)
s.executeLine([]uint8{0xD8})
if s.reg.getFlag(flagD) {
t.Errorf("Error in CLD. %v", s.reg)
}
}
func TestLogic(t *testing.T) {
var s State
s := NewNMOS6502(new(FlatMemory))
s.Reg.setA(0xF0)
executeLine(&s, []uint8{0x29, 0x1C})
if s.Reg.getA() != 0x10 {
t.Errorf("Error in AND <. %v", s.Reg)
s.reg.setA(0xF0)
s.executeLine([]uint8{0x29, 0x1C})
if s.reg.getA() != 0x10 {
t.Errorf("Error in AND <. %v", s.reg)
}
s.Reg.setA(0xF0)
executeLine(&s, []uint8{0x49, 0x1C})
if s.Reg.getA() != 0xEC {
t.Errorf("Error in EOR <. %v", s.Reg)
s.reg.setA(0xF0)
s.executeLine([]uint8{0x49, 0x1C})
if s.reg.getA() != 0xEC {
t.Errorf("Error in EOR <. %v", s.reg)
}
s.Reg.setA(0xF0)
executeLine(&s, []uint8{0x09, 0x0C})
if s.Reg.getA() != 0xFC {
t.Errorf("Error in ORA <. %v", s.Reg)
s.reg.setA(0xF0)
s.executeLine([]uint8{0x09, 0x0C})
if s.reg.getA() != 0xFC {
t.Errorf("Error in ORA <. %v", s.reg)
}
}
func TestAdd(t *testing.T) {
var s State
s := NewNMOS6502(new(FlatMemory))
s.Reg.setA(0xA0)
s.Reg.clearFlag(flagC)
executeLine(&s, []uint8{0x69, 0x0B})
if s.Reg.getA() != 0xAB {
t.Errorf("Error in ADC. %v", s.Reg)
s.reg.setA(0xA0)
s.reg.clearFlag(flagC)
s.executeLine([]uint8{0x69, 0x0B})
if s.reg.getA() != 0xAB {
t.Errorf("Error in ADC. %v", s.reg)
}
if s.Reg.getFlag(flagC) {
t.Errorf("Error in carry ADC. %v", s.Reg)
if s.reg.getFlag(flagC) {
t.Errorf("Error in carry ADC. %v", s.reg)
}
s.Reg.setA(0xFF)
s.Reg.clearFlag(flagC)
executeLine(&s, []uint8{0x69, 0x02})
if s.Reg.getA() != 0x01 {
t.Errorf("Error in ADC with carry. %v", s.Reg)
s.reg.setA(0xFF)
s.reg.clearFlag(flagC)
s.executeLine([]uint8{0x69, 0x02})
if s.reg.getA() != 0x01 {
t.Errorf("Error in ADC with carry. %v", s.reg)
}
if !s.Reg.getFlag(flagC) {
t.Errorf("Error in carry ADC with carry. %v", s.Reg)
if !s.reg.getFlag(flagC) {
t.Errorf("Error in carry ADC with carry. %v", s.reg)
}
s.Reg.setA(0xA0)
s.Reg.setFlag(flagC)
executeLine(&s, []uint8{0x69, 0x01})
if s.Reg.getA() != 0xA2 {
t.Errorf("Error in carried ADC with carry. %v", s.Reg)
s.reg.setA(0xA0)
s.reg.setFlag(flagC)
s.executeLine([]uint8{0x69, 0x01})
if s.reg.getA() != 0xA2 {
t.Errorf("Error in carried ADC with carry. %v", s.reg)
}
if s.Reg.getFlag(flagC) {
t.Errorf("Error in carry in carried ADC with carry. %v", s.Reg)
if s.reg.getFlag(flagC) {
t.Errorf("Error in carry in carried ADC with carry. %v", s.reg)
}
}
func TestAddDecimal(t *testing.T) {
var s State
s.Reg.setFlag(flagD)
s := NewNMOS6502(new(FlatMemory))
s.reg.setFlag(flagD)
s.Reg.setA(0x12)
s.Reg.clearFlag(flagC)
executeLine(&s, []uint8{0x69, 0x013})
if s.Reg.getA() != 0x25 {
t.Errorf("Error in ADC decimal. %v", s.Reg)
s.reg.setA(0x12)
s.reg.clearFlag(flagC)
s.executeLine([]uint8{0x69, 0x013})
if s.reg.getA() != 0x25 {
t.Errorf("Error in ADC decimal. %v", s.reg)
}
if s.Reg.getFlag(flagC) {
t.Errorf("Error in carry ADC. %v", s.Reg)
if s.reg.getFlag(flagC) {
t.Errorf("Error in carry ADC. %v", s.reg)
}
s.Reg.setA(0x44)
s.Reg.clearFlag(flagC)
executeLine(&s, []uint8{0x69, 0x68})
if s.Reg.getA() != 0x12 {
t.Errorf("Error in ADC decimal with carry. %v", s.Reg)
s.reg.setA(0x44)
s.reg.clearFlag(flagC)
s.executeLine([]uint8{0x69, 0x68})
if s.reg.getA() != 0x12 {
t.Errorf("Error in ADC decimal with carry. %v", s.reg)
}
if !s.Reg.getFlag(flagC) {
t.Errorf("Error in carry ADC decimal with carry. %v", s.Reg)
if !s.reg.getFlag(flagC) {
t.Errorf("Error in carry ADC decimal with carry. %v", s.reg)
}
s.Reg.setA(0x44)
s.Reg.setFlag(flagC)
executeLine(&s, []uint8{0x69, 0x23})
if s.Reg.getA() != 0x68 {
t.Errorf("Error in carried ADC decimal with carry. %v", s.Reg)
s.reg.setA(0x44)
s.reg.setFlag(flagC)
s.executeLine([]uint8{0x69, 0x23})
if s.reg.getA() != 0x68 {
t.Errorf("Error in carried ADC decimal with carry. %v", s.reg)
}
if s.Reg.getFlag(flagC) {
t.Errorf("Error in carry in carried ADC decimal with carry. %v", s.Reg)
if s.reg.getFlag(flagC) {
t.Errorf("Error in carry in carried ADC decimal with carry. %v", s.reg)
}
}
func TestSub(t *testing.T) {
var s State
s := NewNMOS6502(new(FlatMemory))
s.Reg.setA(0x09)
s.Reg.clearFlag(flagC)
executeLine(&s, []uint8{0xE9, 0x05})
if s.Reg.getA() != 0x03 {
t.Errorf("Error in SBC. %v", s.Reg)
s.reg.setA(0x09)
s.reg.clearFlag(flagC)
s.executeLine([]uint8{0xE9, 0x05})
if s.reg.getA() != 0x03 {
t.Errorf("Error in SBC. %v", s.reg)
}
if !s.Reg.getFlag(flagC) {
t.Errorf("Error in carry SBC. %v", s.Reg)
if !s.reg.getFlag(flagC) {
t.Errorf("Error in carry SBC. %v", s.reg)
}
s.Reg.setA(0x01)
s.Reg.clearFlag(flagC)
executeLine(&s, []uint8{0xE9, 0x02})
if s.Reg.getA() != 0xFE {
t.Errorf("Error in SBC with carry. %v", s.Reg)
s.reg.setA(0x01)
s.reg.clearFlag(flagC)
s.executeLine([]uint8{0xE9, 0x02})
if s.reg.getA() != 0xFE {
t.Errorf("Error in SBC with carry. %v", s.reg)
}
if s.Reg.getFlag(flagC) {
t.Errorf("Error in carry SBC with carry. %v", s.Reg)
if s.reg.getFlag(flagC) {
t.Errorf("Error in carry SBC with carry. %v", s.reg)
}
s.Reg.setA(0x08)
s.Reg.setFlag(flagC)
executeLine(&s, []uint8{0xE9, 0x02})
if s.Reg.getA() != 0x06 {
t.Errorf("Error in carried SBC with carry. %v", s.Reg)
s.reg.setA(0x08)
s.reg.setFlag(flagC)
s.executeLine([]uint8{0xE9, 0x02})
if s.reg.getA() != 0x06 {
t.Errorf("Error in carried SBC with carry. %v", s.reg)
}
if !s.Reg.getFlag(flagC) {
t.Errorf("Error in carry in carried SBC with carry. %v", s.Reg)
if !s.reg.getFlag(flagC) {
t.Errorf("Error in carry in carried SBC with carry. %v", s.reg)
}
}
func TestCompare(t *testing.T) {
var s State
s := NewNMOS6502(new(FlatMemory))
s.Reg.setA(0x02)
executeLine(&s, []uint8{0xC9, 0x01})
if s.Reg.getP() != 0x01 {
t.Errorf("Error in CMP <. %v", s.Reg)
s.reg.setA(0x02)
s.executeLine([]uint8{0xC9, 0x01})
if s.reg.getP() != 0x01 {
t.Errorf("Error in CMP <. %v", s.reg)
}
executeLine(&s, []uint8{0xC9, 0x02})
if s.Reg.getP() != 0x03 {
t.Errorf("Error in CMP =. %v", s.Reg)
s.executeLine([]uint8{0xC9, 0x02})
if s.reg.getP() != 0x03 {
t.Errorf("Error in CMP =. %v", s.reg)
}
executeLine(&s, []uint8{0xC9, 0x03})
if s.Reg.getP() != 0x80 {
t.Errorf("Error in CMP >. %v", s.Reg)
s.executeLine([]uint8{0xC9, 0x03})
if s.reg.getP() != 0x80 {
t.Errorf("Error in CMP >. %v", s.reg)
}
s.Reg.setX(0x04)
executeLine(&s, []uint8{0xE0, 0x05})
if s.Reg.getP() != 0x80 {
t.Errorf("Error in CPX >. %v", s.Reg)
s.reg.setX(0x04)
s.executeLine([]uint8{0xE0, 0x05})
if s.reg.getP() != 0x80 {
t.Errorf("Error in CPX >. %v", s.reg)
}
s.Reg.setY(0x08)
executeLine(&s, []uint8{0xC0, 0x09})
if s.Reg.getP() != 0x80 {
t.Errorf("Error in CPY >. %v", s.Reg)
s.reg.setY(0x08)
s.executeLine([]uint8{0xC0, 0x09})
if s.reg.getP() != 0x80 {
t.Errorf("Error in CPY >. %v", s.reg)
}
}
func TestBit(t *testing.T) {
var s State
s.Mem = new(FlatMemory)
s := NewNMOS6502(new(FlatMemory))
s.Reg.setA(0x0F)
s.Mem.Poke(0x0040, 0xF0)
executeLine(&s, []uint8{0x24, 0x40})
if s.Reg.getP() != 0xC2 {
t.Errorf("Error in BIT. %v", s.Reg)
s.reg.setA(0x0F)
s.mem.Poke(0x0040, 0xF0)
s.executeLine([]uint8{0x24, 0x40})
if s.reg.getP() != 0xC2 {
t.Errorf("Error in BIT. %v", s.reg)
}
s.Reg.setA(0xF0)
s.Mem.Poke(0x0040, 0xF0)
executeLine(&s, []uint8{0x24, 0x40})
if s.Reg.getP() != 0xC0 {
t.Errorf("Error in BIT, 2. %v", s.Reg)
s.reg.setA(0xF0)
s.mem.Poke(0x0040, 0xF0)
s.executeLine([]uint8{0x24, 0x40})
if s.reg.getP() != 0xC0 {
t.Errorf("Error in BIT, 2. %v", s.reg)
}
s.Reg.setA(0xF0)
s.Mem.Poke(0x01240, 0x80)
executeLine(&s, []uint8{0x2C, 0x40, 0x12})
if s.Reg.getP() != 0x80 {
t.Errorf("Error in BIT, 2. %v", s.Reg)
s.reg.setA(0xF0)
s.mem.Poke(0x01240, 0x80)
s.executeLine([]uint8{0x2C, 0x40, 0x12})
if s.reg.getP() != 0x80 {
t.Errorf("Error in BIT, 2. %v", s.reg)
}
}
func TestBranch(t *testing.T) {
var s State
s := NewNMOS6502(new(FlatMemory))
s.Reg.setPC(0xC600)
s.Reg.setFlag(flagV)
executeLine(&s, []uint8{0x50, 0x20})
if s.Reg.getPC() != 0xC600 {
t.Errorf("Error in BVC, %v", s.Reg)
s.reg.setPC(0xC600)
s.reg.setFlag(flagV)
s.executeLine([]uint8{0x50, 0x20})
if s.reg.getPC() != 0xC600 {
t.Errorf("Error in BVC, %v", s.reg)
}
executeLine(&s, []uint8{0x70, 0x20})
if s.Reg.getPC() != 0xC620 {
t.Errorf("Error in BVS, %v", s.Reg)
s.executeLine([]uint8{0x70, 0x20})
if s.reg.getPC() != 0xC620 {
t.Errorf("Error in BVS, %v", s.reg)
}
s.Reg.setPC(0xD600)
s.Reg.clearFlag(flagC)
executeLine(&s, []uint8{0x90, 0xA0})
if s.Reg.getPC() != 0xD5A0 {
t.Errorf("Error in BCC, %v", s.Reg)
s.reg.setPC(0xD600)
s.reg.clearFlag(flagC)
s.executeLine([]uint8{0x90, 0xA0})
if s.reg.getPC() != 0xD5A0 {
t.Errorf("Error in BCC, %v", s.reg)
}
}
func TestStack(t *testing.T) {
var s State
s.Mem = new(FlatMemory)
s := NewNMOS6502(new(FlatMemory))
s.Reg.setSP(0xF0)
s.Reg.setA(0xA0)
s.Reg.setP(0x0A)
executeLine(&s, []uint8{0x48})
if s.Reg.getSP() != 0xEF {
t.Errorf("Error in PHA stack pointer, %v", s.Reg)
s.reg.setSP(0xF0)
s.reg.setA(0xA0)
s.reg.setP(0x0A)
s.executeLine([]uint8{0x48})
if s.reg.getSP() != 0xEF {
t.Errorf("Error in PHA stack pointer, %v", s.reg)
}
if s.Mem.Peek(0x01F0) != 0xA0 {
t.Errorf("Error in PHA, %v", s.Reg)
if s.mem.Peek(0x01F0) != 0xA0 {
t.Errorf("Error in PHA, %v", s.reg)
}
executeLine(&s, []uint8{0x08})
if s.Reg.getSP() != 0xEE {
t.Errorf("Error in PHP stack pointer, %v", s.Reg)
s.executeLine([]uint8{0x08})
if s.reg.getSP() != 0xEE {
t.Errorf("Error in PHP stack pointer, %v", s.reg)
}
if s.Mem.Peek(0x01EF) != 0x3A {
t.Errorf("Error in PHP, %v", s.Reg)
if s.mem.Peek(0x01EF) != 0x3A {
t.Errorf("Error in PHP, %v", s.reg)
}
executeLine(&s, []uint8{0x68})
if s.Reg.getSP() != 0xEF {
t.Errorf("Error in PLA stack pointer, %v", s.Reg)
s.executeLine([]uint8{0x68})
if s.reg.getSP() != 0xEF {
t.Errorf("Error in PLA stack pointer, %v", s.reg)
}
if s.Reg.getA() != 0x3A {
t.Errorf("Error in PLA, %v", s.Reg)
if s.reg.getA() != 0x3A {
t.Errorf("Error in PLA, %v", s.reg)
}
executeLine(&s, []uint8{0x28})
if s.Reg.getSP() != 0xF0 {
t.Errorf("Error in PLP stack pointer, %v", s.Reg)
s.executeLine([]uint8{0x28})
if s.reg.getSP() != 0xF0 {
t.Errorf("Error in PLP stack pointer, %v", s.reg)
}
if s.Reg.getP() != 0xA0 {
t.Errorf("Error in PLP, %v", s.Reg)
if s.reg.getP() != 0xA0 {
t.Errorf("Error in PLP, %v", s.reg)
}
}

184
core6502/opcodesNMOS6502.go Normal file
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package core6502
// NewNMOS6502 returns an initialized NMOS6502
func NewNMOS6502(m Memory) *State {
var s State
s.mem = m
s.opcodes = &opcodesNMOS6502
return &s
}
var opcodesNMOS6502 = [256]opcode{
0x00: opcode{"BRK", 1, 7, modeImplicit, opBRK},
0x4C: opcode{"JMP", 3, 3, modeAbsolute, opJMP},
0x6C: opcode{"JMP", 3, 3, modeIndirect, opJMP},
0x20: opcode{"JSR", 3, 6, modeAbsolute, opJSR},
0x40: opcode{"RTI", 1, 6, modeImplicit, opRTI},
0x60: opcode{"RTS", 1, 6, modeImplicit, opRTS},
0x48: opcode{"PHA", 1, 3, modeImplicit, opPHA},
0x08: opcode{"PHP", 1, 3, modeImplicit, opPHP},
0x68: opcode{"PLA", 1, 4, modeImplicit, opPLA},
0x28: opcode{"PLP", 1, 4, modeImplicit, opPLP},
0x09: opcode{"ORA", 2, 2, modeImmediate, buildOpLogic(operationOr)},
0x05: opcode{"ORA", 2, 3, modeZeroPage, buildOpLogic(operationOr)},
0x15: opcode{"ORA", 2, 4, modeZeroPageX, buildOpLogic(operationOr)},
0x0D: opcode{"ORA", 3, 4, modeAbsolute, buildOpLogic(operationOr)},
0x1D: opcode{"ORA", 3, 4, modeAbsoluteX, buildOpLogic(operationOr)}, // Extra cycles
0x19: opcode{"ORA", 3, 4, modeAbsoluteY, buildOpLogic(operationOr)}, // Extra cycles
0x01: opcode{"ORA", 2, 6, modeIndexedIndirectX, buildOpLogic(operationOr)},
0x11: opcode{"ORA", 2, 5, modeIndirectIndexedY, buildOpLogic(operationOr)}, // Extra cycles
0x29: opcode{"AND", 2, 2, modeImmediate, buildOpLogic(operationAnd)},
0x25: opcode{"AND", 2, 3, modeZeroPage, buildOpLogic(operationAnd)},
0x35: opcode{"AND", 2, 4, modeZeroPageX, buildOpLogic(operationAnd)},
0x2D: opcode{"AND", 3, 4, modeAbsolute, buildOpLogic(operationAnd)},
0x3D: opcode{"AND", 3, 4, modeAbsoluteX, buildOpLogic(operationAnd)}, // Extra cycles
0x39: opcode{"AND", 3, 4, modeAbsoluteY, buildOpLogic(operationAnd)}, // Extra cycles
0x21: opcode{"AND", 2, 6, modeIndexedIndirectX, buildOpLogic(operationAnd)},
0x31: opcode{"AND", 2, 5, modeIndirectIndexedY, buildOpLogic(operationAnd)}, // Extra cycles
0x49: opcode{"EOR", 2, 2, modeImmediate, buildOpLogic(operationXor)},
0x45: opcode{"EOR", 2, 3, modeZeroPage, buildOpLogic(operationXor)},
0x55: opcode{"EOR", 2, 4, modeZeroPageX, buildOpLogic(operationXor)},
0x4D: opcode{"EOR", 3, 4, modeAbsolute, buildOpLogic(operationXor)},
0x5D: opcode{"EOR", 3, 4, modeAbsoluteX, buildOpLogic(operationXor)}, // Extra cycles
0x59: opcode{"EOR", 3, 4, modeAbsoluteY, buildOpLogic(operationXor)}, // Extra cycles
0x41: opcode{"EOR", 2, 6, modeIndexedIndirectX, buildOpLogic(operationXor)},
0x51: opcode{"EOR", 2, 5, modeIndirectIndexedY, buildOpLogic(operationXor)}, // Extra cycles
0x69: opcode{"ADC", 2, 2, modeImmediate, opADC},
0x65: opcode{"ADC", 2, 3, modeZeroPage, opADC},
0x75: opcode{"ADC", 2, 4, modeZeroPageX, opADC},
0x6D: opcode{"ADC", 3, 4, modeAbsolute, opADC},
0x7D: opcode{"ADC", 3, 4, modeAbsoluteX, opADC}, // Extra cycles
0x79: opcode{"ADC", 3, 4, modeAbsoluteY, opADC}, // Extra cycles
0x61: opcode{"ADC", 2, 6, modeIndexedIndirectX, opADC},
0x71: opcode{"ADC", 2, 5, modeIndirectIndexedY, opADC}, // Extra cycles
0xE9: opcode{"SBC", 2, 2, modeImmediate, opSBC},
0xE5: opcode{"SBC", 2, 3, modeZeroPage, opSBC},
0xF5: opcode{"SBC", 2, 4, modeZeroPageX, opSBC},
0xED: opcode{"SBC", 3, 4, modeAbsolute, opSBC},
0xFD: opcode{"SBC", 3, 4, modeAbsoluteX, opSBC}, // Extra cycles
0xF9: opcode{"SBC", 3, 4, modeAbsoluteY, opSBC}, // Extra cycles
0xE1: opcode{"SBC", 2, 6, modeIndexedIndirectX, opSBC},
0xF1: opcode{"SBC", 2, 5, modeIndirectIndexedY, opSBC}, // Extra cycles
0x24: opcode{"BIT", 2, 3, modeZeroPage, opBIT},
0x2C: opcode{"BIT", 3, 3, modeAbsolute, opBIT},
0xC9: opcode{"CMP", 2, 2, modeImmediate, buildOpCompare(regA)},
0xC5: opcode{"CMP", 2, 3, modeZeroPage, buildOpCompare(regA)},
0xD5: opcode{"CMP", 2, 4, modeZeroPageX, buildOpCompare(regA)},
0xCD: opcode{"CMP", 3, 4, modeAbsolute, buildOpCompare(regA)},
0xDD: opcode{"CMP", 3, 4, modeAbsoluteX, buildOpCompare(regA)}, // Extra cycles
0xD9: opcode{"CMP", 3, 4, modeAbsoluteY, buildOpCompare(regA)}, // Extra cycles
0xC1: opcode{"CMP", 2, 6, modeIndexedIndirectX, buildOpCompare(regA)},
0xD1: opcode{"CMP", 2, 5, modeIndirectIndexedY, buildOpCompare(regA)}, // Extra cycles
0xE0: opcode{"CPX", 2, 2, modeImmediate, buildOpCompare(regX)},
0xE4: opcode{"CPX", 2, 3, modeZeroPage, buildOpCompare(regX)},
0xEC: opcode{"CPX", 3, 4, modeAbsolute, buildOpCompare(regX)},
0xC0: opcode{"CPY", 2, 2, modeImmediate, buildOpCompare(regY)},
0xC4: opcode{"CPY", 2, 3, modeZeroPage, buildOpCompare(regY)},
0xCC: opcode{"CPY", 3, 4, modeAbsolute, buildOpCompare(regY)},
0x2A: opcode{"ROL", 1, 2, modeAccumulator, buildOpShift(true, true)},
0x26: opcode{"ROL", 2, 5, modeZeroPage, buildOpShift(true, true)},
0x36: opcode{"ROL", 2, 6, modeZeroPageX, buildOpShift(true, true)},
0x2E: opcode{"ROL", 3, 6, modeAbsolute, buildOpShift(true, true)},
0x3E: opcode{"ROL", 3, 7, modeAbsoluteX, buildOpShift(true, true)},
0x6A: opcode{"ROR", 1, 2, modeAccumulator, buildOpShift(false, true)},
0x66: opcode{"ROR", 2, 5, modeZeroPage, buildOpShift(false, true)},
0x76: opcode{"ROR", 2, 6, modeZeroPageX, buildOpShift(false, true)},
0x6E: opcode{"ROR", 3, 6, modeAbsolute, buildOpShift(false, true)},
0x7E: opcode{"ROR", 3, 7, modeAbsoluteX, buildOpShift(false, true)},
0x0A: opcode{"ASL", 1, 2, modeAccumulator, buildOpShift(true, false)},
0x06: opcode{"ASL", 2, 5, modeZeroPage, buildOpShift(true, false)},
0x16: opcode{"ASL", 2, 6, modeZeroPageX, buildOpShift(true, false)},
0x0E: opcode{"ASL", 3, 6, modeAbsolute, buildOpShift(true, false)},
0x1E: opcode{"ASL", 3, 7, modeAbsoluteX, buildOpShift(true, false)},
0x4A: opcode{"LSR", 1, 2, modeAccumulator, buildOpShift(false, false)},
0x46: opcode{"LSR", 2, 5, modeZeroPage, buildOpShift(false, false)},
0x56: opcode{"LSR", 2, 6, modeZeroPageX, buildOpShift(false, false)},
0x4E: opcode{"LSR", 3, 6, modeAbsolute, buildOpShift(false, false)},
0x5E: opcode{"LSR", 3, 7, modeAbsoluteX, buildOpShift(false, false)},
0x38: opcode{"SEC", 1, 2, modeImplicit, buildOpUpdateFlag(flagC, true)},
0xF8: opcode{"SED", 1, 2, modeImplicit, buildOpUpdateFlag(flagD, true)},
0x78: opcode{"SEI", 1, 2, modeImplicit, buildOpUpdateFlag(flagI, true)},
0x18: opcode{"CLC", 1, 2, modeImplicit, buildOpUpdateFlag(flagC, false)},
0xD8: opcode{"CLD", 1, 2, modeImplicit, buildOpUpdateFlag(flagD, false)},
0x58: opcode{"CLI", 1, 2, modeImplicit, buildOpUpdateFlag(flagI, false)},
0xB8: opcode{"CLV", 1, 2, modeImplicit, buildOpUpdateFlag(flagV, false)},
0xE6: opcode{"INC", 2, 5, modeZeroPage, buildOpIncDec(true)},
0xF6: opcode{"INC", 2, 6, modeZeroPageX, buildOpIncDec(true)},
0xEE: opcode{"INC", 3, 6, modeAbsolute, buildOpIncDec(true)},
0xFE: opcode{"INC", 3, 7, modeAbsoluteX, buildOpIncDec(true)},
0xC6: opcode{"DEC", 2, 5, modeZeroPage, buildOpIncDec(false)},
0xD6: opcode{"DEC", 2, 6, modeZeroPageX, buildOpIncDec(false)},
0xCE: opcode{"DEC", 3, 6, modeAbsolute, buildOpIncDec(false)},
0xDE: opcode{"DEC", 3, 7, modeAbsoluteX, buildOpIncDec(false)},
0xE8: opcode{"INX", 1, 2, modeImplicitX, buildOpIncDec(true)},
0xC8: opcode{"INY", 1, 2, modeImplicitY, buildOpIncDec(true)},
0xCA: opcode{"DEX", 1, 2, modeImplicitX, buildOpIncDec(false)},
0x88: opcode{"DEY", 1, 2, modeImplicitY, buildOpIncDec(false)},
0xAA: opcode{"TAX", 1, 2, modeImplicit, buildOpTransfer(regA, regX)},
0xA8: opcode{"TAY", 1, 2, modeImplicit, buildOpTransfer(regA, regY)},
0x8A: opcode{"TXA", 1, 2, modeImplicit, buildOpTransfer(regX, regA)},
0x98: opcode{"TYA", 1, 2, modeImplicit, buildOpTransfer(regY, regA)},
0x9A: opcode{"TXS", 1, 2, modeImplicit, buildOpTransfer(regX, regSP)},
0xBA: opcode{"TSX", 1, 2, modeImplicit, buildOpTransfer(regSP, regX)},
0xA9: opcode{"LDA", 2, 2, modeImmediate, buildOpLoad(regA)},
0xA5: opcode{"LDA", 2, 3, modeZeroPage, buildOpLoad(regA)},
0xB5: opcode{"LDA", 2, 4, modeZeroPageX, buildOpLoad(regA)},
0xAD: opcode{"LDA", 3, 4, modeAbsolute, buildOpLoad(regA)},
0xBD: opcode{"LDA", 3, 4, modeAbsoluteX, buildOpLoad(regA)}, // Extra cycles
0xB9: opcode{"LDA", 3, 4, modeAbsoluteY, buildOpLoad(regA)}, // Extra cycles
0xA1: opcode{"LDA", 2, 6, modeIndexedIndirectX, buildOpLoad(regA)},
0xB1: opcode{"LDA", 2, 5, modeIndirectIndexedY, buildOpLoad(regA)}, // Extra cycles
0xA2: opcode{"LDX", 2, 2, modeImmediate, buildOpLoad(regX)},
0xA6: opcode{"LDX", 2, 3, modeZeroPage, buildOpLoad(regX)},
0xB6: opcode{"LDX", 2, 4, modeZeroPageY, buildOpLoad(regX)},
0xAE: opcode{"LDX", 3, 4, modeAbsolute, buildOpLoad(regX)},
0xBE: opcode{"LDX", 3, 4, modeAbsoluteY, buildOpLoad(regX)}, // Extra cycles
0xA0: opcode{"LDY", 2, 2, modeImmediate, buildOpLoad(regY)},
0xA4: opcode{"LDY", 2, 3, modeZeroPage, buildOpLoad(regY)},
0xB4: opcode{"LDY", 2, 4, modeZeroPageX, buildOpLoad(regY)},
0xAC: opcode{"LDY", 3, 4, modeAbsolute, buildOpLoad(regY)},
0xBC: opcode{"LDY", 3, 4, modeAbsoluteX, buildOpLoad(regY)}, // Extra cycles
0x85: opcode{"STA", 2, 3, modeZeroPage, buildOpStore(regA)},
0x95: opcode{"STA", 2, 4, modeZeroPageX, buildOpStore(regA)},
0x8D: opcode{"STA", 3, 4, modeAbsolute, buildOpStore(regA)},
0x9D: opcode{"STA", 3, 5, modeAbsoluteX, buildOpStore(regA)},
0x99: opcode{"STA", 3, 5, modeAbsoluteY, buildOpStore(regA)},
0x81: opcode{"STA", 2, 6, modeIndexedIndirectX, buildOpStore(regA)},
0x91: opcode{"STA", 2, 6, modeIndirectIndexedY, buildOpStore(regA)},
0x86: opcode{"STX", 2, 3, modeZeroPage, buildOpStore(regX)},
0x96: opcode{"STX", 2, 4, modeZeroPageY, buildOpStore(regX)},
0x8E: opcode{"STX", 3, 4, modeAbsolute, buildOpStore(regX)},
0x84: opcode{"STY", 2, 3, modeZeroPage, buildOpStore(regY)},
0x94: opcode{"STY", 2, 4, modeZeroPageX, buildOpStore(regY)},
0x8C: opcode{"STY", 3, 4, modeAbsolute, buildOpStore(regY)},
0x90: opcode{"BCC", 2, 2, modeRelative, buildOpBranch(flagC, false)}, // Extra cycles
0xB0: opcode{"BCS", 2, 2, modeRelative, buildOpBranch(flagC, true)}, // Extra cycles
0xD0: opcode{"BNE", 2, 2, modeRelative, buildOpBranch(flagZ, false)}, // Extra cycles
0xF0: opcode{"BEQ", 2, 2, modeRelative, buildOpBranch(flagZ, true)}, // Extra cycles
0x10: opcode{"BPL", 2, 2, modeRelative, buildOpBranch(flagN, false)}, // Extra cycles
0x30: opcode{"BMI", 2, 2, modeRelative, buildOpBranch(flagN, true)}, // Extra cycles
0x50: opcode{"BVC", 2, 2, modeRelative, buildOpBranch(flagV, false)}, // Extra cycles
0x70: opcode{"BVS", 2, 2, modeRelative, buildOpBranch(flagV, true)}, // Extra cycles
0xEA: opcode{"NOP", 1, 2, modeImplicit, opNOP},
}

242
core6502/operations.go Normal file
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package core6502
func buildOpTransfer(regSrc int, regDst int) opFunc {
return func(s *State, line []uint8, opcode opcode) {
value := s.reg.getRegister(regSrc)
s.reg.setRegister(regDst, value)
if regDst != regSP {
s.reg.updateFlagZN(value)
}
}
}
func buildOpIncDec(inc bool) opFunc {
return func(s *State, line []uint8, opcode opcode) {
value, setValue := resolveGetSetValue(s, line, opcode)
if inc {
value++
} else {
value--
}
s.reg.updateFlagZN(value)
setValue(value)
}
}
func buildOpShift(isLeft bool, isRotate bool) opFunc {
return func(s *State, line []uint8, opcode opcode) {
value, setValue := resolveGetSetValue(s, line, opcode)
oldCarry := s.reg.getFlagBit(flagC)
var carry bool
if isLeft {
carry = (value & 0x80) != 0
value <<= 1
if isRotate {
value += oldCarry
}
} else {
carry = (value & 0x01) != 0
value >>= 1
if isRotate {
value += oldCarry << 7
}
}
s.reg.updateFlag(flagC, carry)
s.reg.updateFlagZN(value)
setValue(value)
}
}
func buildOpLoad(regDst int) opFunc {
return func(s *State, line []uint8, opcode opcode) {
value := resolveValue(s, line, opcode)
s.reg.setRegister(regDst, value)
s.reg.updateFlagZN(value)
}
}
func buildOpStore(regSrc int) opFunc {
return func(s *State, line []uint8, opcode opcode) {
setValue := resolveSetValue(s, line, opcode)
value := s.reg.getRegister(regSrc)
setValue(value)
}
}
func buildOpUpdateFlag(flag uint8, value bool) opFunc {
return func(s *State, line []uint8, opcode opcode) {
s.reg.updateFlag(flag, value)
}
}
func buildOpBranch(flag uint8, value bool) opFunc {
return func(s *State, line []uint8, opcode opcode) {
if s.reg.getFlag(flag) == value {
// This assumes that PC is already pointing to the next instruction
pc := s.reg.getPC()
pc += uint16(int8(line[1]))
s.reg.setPC(pc)
}
}
}
func opBIT(s *State, line []uint8, opcode opcode) {
value := resolveValue(s, line, opcode)
acc := s.reg.getA()
// Future note: The immediate addressing mode (65C02 or 65816 only) does not affect V.
s.reg.updateFlag(flagZ, value&acc == 0)
s.reg.updateFlag(flagN, value&(1<<7) != 0)
s.reg.updateFlag(flagV, value&(1<<6) != 0)
}
func buildOpCompare(reg int) opFunc {
return func(s *State, line []uint8, opcode opcode) {
value := resolveValue(s, line, opcode)
reference := s.reg.getRegister(reg)
s.reg.updateFlagZN(reference - value)
s.reg.updateFlag(flagC, reference >= value)
}
}
func operationAnd(a uint8, b uint8) uint8 { return a & b }
func operationOr(a uint8, b uint8) uint8 { return a | b }
func operationXor(a uint8, b uint8) uint8 { return a ^ b }
func buildOpLogic(operation func(uint8, uint8) uint8) opFunc {
return func(s *State, line []uint8, opcode opcode) {
value := resolveValue(s, line, opcode)
result := operation(value, s.reg.getA())
s.reg.setA(result)
s.reg.updateFlagZN(result)
}
}
func opADC(s *State, line []uint8, opcode opcode) {
value := resolveValue(s, line, opcode)
aValue := s.reg.getA()
carry := s.reg.getFlagBit(flagC)
total := uint16(aValue) + uint16(value) + uint16(carry)
signedTotal := int16(int8(aValue)) + int16(int8(value)) + int16(carry)
truncated := uint8(total)
if s.reg.getFlag(flagD) {
totalBcdLo := int(aValue&0x0f) + int(value&0x0f) + int(carry)
totalBcdHi := int(aValue>>4) + int(value>>4)
if totalBcdLo >= 10 {
totalBcdHi++
}
totalBcd := (totalBcdHi%10)<<4 + (totalBcdLo % 10)
s.reg.setA(uint8(totalBcd))
s.reg.updateFlag(flagC, totalBcdHi > 9)
} else {
s.reg.setA(truncated)
s.reg.updateFlag(flagC, total > 0xFF)
}
// ZNV flags behave for BCD as if the operation was binary?
s.reg.updateFlagZN(truncated)
s.reg.updateFlag(flagV, signedTotal < -128 || signedTotal > 127)
}
func opSBC(s *State, line []uint8, opcode opcode) {
value := resolveValue(s, line, opcode)
aValue := s.reg.getA()
carry := s.reg.getFlagBit(flagC)
total := 0x100 + uint16(aValue) - uint16(value) + uint16(carry) - 1
signedTotal := int16(int8(aValue)) - int16(int8(value)) + int16(carry) - 1
truncated := uint8(total)
if s.reg.getFlag(flagD) {
totalBcdLo := 10 + int(aValue&0x0f) - int(value&0x0f) + int(carry) - 1
totalBcdHi := 10 + int(aValue>>4) - int(value>>4)
if totalBcdLo < 10 {
totalBcdHi--
}
totalBcd := (totalBcdHi%10)<<4 + (totalBcdLo % 10)
s.reg.setA(uint8(totalBcd))
s.reg.updateFlag(flagC, totalBcdHi >= 10)
} else {
s.reg.setA(truncated)
s.reg.updateFlag(flagC, total > 0xFF)
}
// ZNV flags behave for SBC as if the operation was binary
s.reg.updateFlagZN(truncated)
s.reg.updateFlag(flagV, signedTotal < -128 || signedTotal > 127)
}
const stackAddress uint16 = 0x0100
func pushByte(s *State, value uint8) {
adresss := stackAddress + uint16(s.reg.getSP())
s.mem.Poke(adresss, value)
s.reg.setSP(s.reg.getSP() - 1)
}
func pullByte(s *State) uint8 {
s.reg.setSP(s.reg.getSP() + 1)
adresss := stackAddress + uint16(s.reg.getSP())
return s.mem.Peek(adresss)
}
func pushWord(s *State, value uint16) {
pushByte(s, uint8(value>>8))
pushByte(s, uint8(value))
}
func pullWord(s *State) uint16 {
return uint16(pullByte(s)) +
(uint16(pullByte(s)) << 8)
}
func opPLA(s *State, line []uint8, opcode opcode) {
value := pullByte(s)
s.reg.setA(value)
s.reg.updateFlagZN(value)
}
func opPLP(s *State, line []uint8, opcode opcode) {
value := pullByte(s)
s.reg.setP(value)
}
func opPHA(s *State, line []uint8, opcode opcode) {
pushByte(s, s.reg.getA())
}
func opPHP(s *State, line []uint8, opcode opcode) {
pushByte(s, s.reg.getP()|(flagB+flag5))
}
func opJMP(s *State, line []uint8, opcode opcode) {
address := resolveAddress(s, line, opcode)
s.reg.setPC(address)
}
func opNOP(s *State, line []uint8, opcode opcode) {}
func opJSR(s *State, line []uint8, opcode opcode) {
pushWord(s, s.reg.getPC()-1)
address := resolveAddress(s, line, opcode)
s.reg.setPC(address)
}
func opRTI(s *State, line []uint8, opcode opcode) {
s.reg.setP(pullByte(s))
s.reg.setPC(pullWord(s))
}
func opRTS(s *State, line []uint8, opcode opcode) {
s.reg.setPC(pullWord(s) + 1)
}
func opBRK(s *State, line []uint8, opcode opcode) {
pushWord(s, s.reg.getPC()+1)
pushByte(s, s.reg.getP()|(flagB+flag5))
s.reg.setFlag(flagI)
s.reg.setPC(getWord(s.mem, vectorBreak))
}