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izapple2
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Support for ASL and LSR

This commit is contained in:
Ivan Izaguirre 2019-01-30 20:32:11 +01:00
parent 7b1cb65eef
commit 9e73ad1850
2 changed files with 50 additions and 17 deletions
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45
execute.go
View File

@ -123,7 +123,7 @@ func buildOpIncDec(addressMode int, inc bool) opFunc {
}
}
func buildRotate(addressMode int, isLeft bool) opFunc {
func buildShift(addressMode int, isLeft bool, isRotate bool) opFunc {
return func(s *state, line []uint8, opcode opcode) {
value, setValue := resolveWithAddressMode(s, line, addressMode)
@ -132,11 +132,15 @@ func buildRotate(addressMode int, isLeft bool) opFunc {
if isLeft {
carry = (value & 0x80) != 0
value <<= 1
value += oldCarry
if isRotate {
value += oldCarry
}
} else {
carry = (value & 0x01) != 0
value >>= 1
value += oldCarry << 7
if isRotate {
value += oldCarry << 7
}
}
s.registers.updateFlag(flagC, carry)
s.registers.updateFlagZN(value)
@ -185,10 +189,7 @@ SBC
AND
ORA
ASL
EOR
LSR
BIT
CMP
@ -210,17 +211,29 @@ PLP
*/
var opcodes = [256]opcode{
0x2A: opcode{"ROL", 1, 2, buildRotate(modeAccumulator, true)},
0x26: opcode{"ROL", 2, 5, buildRotate(modeZeroPage, true)},
0x36: opcode{"ROL", 2, 6, buildRotate(modeZeroPageX, true)},
0x2E: opcode{"ROL", 3, 6, buildRotate(modeAbsolute, true)},
0x3E: opcode{"ROL", 3, 7, buildRotate(modeAbsoluteX, true)},
0x2A: opcode{"ROL", 1, 2, buildShift(modeAccumulator, true, true)},
0x26: opcode{"ROL", 2, 5, buildShift(modeZeroPage, true, true)},
0x36: opcode{"ROL", 2, 6, buildShift(modeZeroPageX, true, true)},
0x2E: opcode{"ROL", 3, 6, buildShift(modeAbsolute, true, true)},
0x3E: opcode{"ROL", 3, 7, buildShift(modeAbsoluteX, true, true)},
0x6A: opcode{"ROR", 1, 2, buildRotate(modeAccumulator, false)},
0x66: opcode{"ROR", 2, 5, buildRotate(modeZeroPage, false)},
0x76: opcode{"ROR", 2, 6, buildRotate(modeZeroPageX, false)},
0x6E: opcode{"ROR", 3, 6, buildRotate(modeAbsolute, false)},
0x7E: opcode{"ROR", 3, 7, buildRotate(modeAbsoluteX, false)},
0x6A: opcode{"ROR", 1, 2, buildShift(modeAccumulator, false, true)},
0x66: opcode{"ROR", 2, 5, buildShift(modeZeroPage, false, true)},
0x76: opcode{"ROR", 2, 6, buildShift(modeZeroPageX, false, true)},
0x6E: opcode{"ROR", 3, 6, buildShift(modeAbsolute, false, true)},
0x7E: opcode{"ROR", 3, 7, buildShift(modeAbsoluteX, false, true)},
0x0A: opcode{"ASL", 1, 2, buildShift(modeAccumulator, true, false)},
0x06: opcode{"ASL", 2, 5, buildShift(modeZeroPage, true, false)},
0x16: opcode{"ASL", 2, 6, buildShift(modeZeroPageX, true, false)},
0x0E: opcode{"ASL", 3, 6, buildShift(modeAbsolute, true, false)},
0x1E: opcode{"ASL", 3, 7, buildShift(modeAbsoluteX, true, false)},
0x4A: opcode{"LSR", 1, 2, buildShift(modeAccumulator, false, false)},
0x46: opcode{"LSR", 2, 5, buildShift(modeZeroPage, false, false)},
0x56: opcode{"LSR", 2, 6, buildShift(modeZeroPageX, false, false)},
0x4E: opcode{"LSR", 3, 6, buildShift(modeAbsolute, false, false)},
0x5E: opcode{"LSR", 3, 7, buildShift(modeAbsoluteX, false, false)},
0x38: opcode{"SEC", 1, 2, buildOpUpdateFlag(flagC, true)},
0xF8: opcode{"SED", 1, 2, buildOpUpdateFlag(flagD, true)},

22
execute_test.go
View File

@ -179,7 +179,7 @@ func TestIncDec(t *testing.T) {
}
}
func TestRotate(t *testing.T) {
func TestShiftRotate(t *testing.T) {
var s state
s.registers.setA(0xF0)
@ -200,6 +200,26 @@ func TestRotate(t *testing.T) {
if !s.registers.getFlag(flagC) {
t.Errorf("Error in ROR carry")
}
s.registers.setFlag(flagC)
s.registers.setA(0x81)
executeLine(&s, []uint8{0x0A})
if s.registers.getA() != 0x02 {
t.Errorf("Error in ASL. %v", s.registers)
}
if !s.registers.getFlag(flagC) {
t.Errorf("Error in ASL carry")
}
s.registers.setFlag(flagC)
s.registers.setA(0x02)
executeLine(&s, []uint8{0x4A})
if s.registers.getA() != 0x01 {
t.Errorf("Error in LSR. %v", s.registers)
}
if s.registers.getFlag(flagC) {
t.Errorf("Error in LSR carry")
}
}
func TestClearSetFlag(t *testing.T) {