Handle the virtual bits 5 and 4 when pushing P to the stack

execute.go

@@ -274,18 +274,20 @@ func pullWord(s *state) uint16 {
 
 }
 
-func buildOpPush(reg int) opFunc {
-	return func(s *state, line []uint8, opcode opcode) {
-		pushByte(s, s.registers.getRegister(reg))
-	}
-}
-
 func buildOpPull(reg int) opFunc {
 	return func(s *state, line []uint8, opcode opcode) {
 		s.registers.setRegister(reg, pullByte(s))
 	}
 }
 
+func opPHA(s *state, line []uint8, opcode opcode) {
+	pushByte(s, s.registers.getA())
+}
+
+func opPHP(s *state, line []uint8, opcode opcode) {
+	pushByte(s, s.registers.getP()|(flagB+flag5))
+}
+
 func buildOpJump(addressMode int) opFunc {
 	return func(s *state, line []uint8, opcode opcode) {
 		_, address, _ := resolveWithAddressMode(s, line, addressMode)
@@ -312,7 +314,7 @@ func opRTS(s *state, line []uint8, opcode opcode) {
 func opBRK(s *state, line []uint8, opcode opcode) {
 	s.registers.setFlag(flagI)
 	pushWord(s, s.registers.getPC()+1) // TODO: De we have to add 1 or 2?
-	pushByte(s, s.registers.getP())
+	pushByte(s, s.registers.getP()|(flagB+flag5))
 	s.registers.setPC(s.memory.getWord(0xFFFE))
 }
 
@@ -324,8 +326,8 @@ var opcodes = [256]opcode{
 	0x40: opcode{"RTI", 1, 6, opRTI},
 	0x60: opcode{"RTS", 1, 6, opRTS},
 
-	0x48: opcode{"PHA", 1, 3, buildOpPush(regA)},
-	0x08: opcode{"PHP", 1, 3, buildOpPush(regP)},
+	0x48: opcode{"PHA", 1, 3, opPHA},
+	0x08: opcode{"PHP", 1, 3, opPHP},
 	0x68: opcode{"PLA", 1, 4, buildOpPull(regA)},
 	0x28: opcode{"PLP", 1, 4, buildOpPull(regP)},
 

execute_test.go

@@ -427,7 +427,7 @@ func TestStack(t *testing.T) {
 	if s.registers.getSP() != 0xEE {
 		t.Errorf("Error in PHP stack pointer, %v", s.registers)
 	}
-	if s.memory[0x01EF] != 0x0A {
+	if s.memory[0x01EF] != 0x3A {
 		t.Errorf("Error in PHP, %v", s.registers)
 	}
 
@@ -435,7 +435,7 @@ func TestStack(t *testing.T) {
 	if s.registers.getSP() != 0xEF {
 		t.Errorf("Error in PLA stack pointer, %v", s.registers)
 	}
-	if s.registers.getA() != 0x0A {
+	if s.registers.getA() != 0x3A {
 		t.Errorf("Error in PLA, %v", s.registers)
 	}
 
@@ -447,3 +447,5 @@ func TestStack(t *testing.T) {
 		t.Errorf("Error in PLP, %v", s.registers)
 	}
 }
+
+// TODO: Tests for BRK, JMP, JSR, RTI, RTS

registers.go

@@ -15,6 +15,7 @@ const (
 const (
 	flagN uint8 = 1 << 7
 	flagV uint8 = 1 << 6
+	flag5 uint8 = 1 << 5
 	flagB uint8 = 1 << 4
 	flagD uint8 = 1 << 3
 	flagI uint8 = 1 << 2