Refactor memory in pages. Addes text, ram and rom pages

6502functional_test.go

@@ -7,11 +7,12 @@ import (
 
 func TestFunctional(t *testing.T) {
 	var s state
+	// Test suite from https://github.com/Klaus2m5/6502_65C02_functional_tests
 	s.memory.loadBinary("tests/6502_functional_test.bin")
 
 	s.registers.setPC(0x0400)
 	for true {
-		testCase := s.memory[0x0200]
+		testCase := s.memory.peek(0x0200)
 		if testCase >= 240 {
 			break
 		}

execute.go

@@ -82,12 +82,12 @@ func resolve(s *state, line []uint8, opcode opcode) (value uint8, address uint16
 	}
 
 	if hasAddress {
-		value = s.memory[address]
+		value = s.memory.peek(address)
 	}
 
 	setValue = func(value uint8) {
 		if hasAddress {
-			s.memory[address] = value
+			s.memory.poke(address, value)
 		} else if register != regNone {
 			s.registers.setRegister(register, value)
 		} else {
@@ -99,7 +99,7 @@ func resolve(s *state, line []uint8, opcode opcode) (value uint8, address uint16
 
 type opcode struct {
 	name        string
-	bytes       int8
+	bytes       uint8
 	cycles      int
 	addressMode int
 	action      opFunc
@@ -279,14 +279,14 @@ const stackAddress uint16 = 0x0100
 
 func pushByte(s *state, value uint8) {
 	adresss := stackAddress + uint16(s.registers.getSP())
-	s.memory[adresss] = value
+	s.memory.poke(adresss, value)
 	s.registers.setSP(s.registers.getSP() - 1)
 }
 
 func pullByte(s *state) uint8 {
 	s.registers.setSP(s.registers.getSP() + 1)
 	adresss := stackAddress + uint16(s.registers.getSP())
-	return s.memory[adresss]
+	return s.memory.peek(adresss)
 }
 
 func pushWord(s *state, value uint16) {
@@ -530,10 +530,15 @@ func executeLine(s *state, line []uint8) {
 
 func executeInstruction(s *state, log bool) {
 	pc := s.registers.getPC()
-	opcode := opcodes[s.memory[pc]]
-	pcNext := pc + uint16(opcode.bytes)
-	s.registers.setPC(pcNext)
-	line := s.memory[pc:pcNext]
+	opcode := opcodes[s.memory.peek(pc)]
+
+	line := make([]uint8, opcode.bytes)
+	for i := uint8(0); i < opcode.bytes; i++ {
+		line[i] = s.memory.peek(pc)
+		pc++
+	}
+	s.registers.setPC(pc)
+
 	if log {
 		fmt.Printf("%#04x %-12s: ", pc, lineString(s, line, opcode))
 	}

execute_test.go

@@ -6,6 +6,7 @@ import (
 
 func TestLoad(t *testing.T) {
 	var s state
+	s.memory.initWithRam()
 
 	executeLine(&s, []uint8{0xA9, 0x42})
 	if s.registers.getA() != 0x42 {
@@ -27,59 +28,59 @@ func TestLoad(t *testing.T) {
 		t.Error("Error in LDY #")
 	}
 
-	s.memory[0x38] = 0x87
+	s.memory.poke(0x38, 0x87)
 	executeLine(&s, []uint8{0xA5, 0x38})
 	if s.registers.getA() != 0x87 {
 		t.Error("Error in LDA zpg")
 	}
 
-	s.memory[0x57] = 0x90
+	s.memory.poke(0x57, 0x90)
 	s.registers.setX(0x10)
 	executeLine(&s, []uint8{0xB5, 0x47})
 	if s.registers.getA() != 0x90 {
 		t.Error("Error in LDA zpg, X")
 	}
 
-	s.memory[0x38] = 0x12
+	s.memory.poke(0x38, 0x12)
 	s.registers.setX(0x89)
 	executeLine(&s, []uint8{0xB5, 0xAF})
 	if s.registers.getA() != 0x12 {
 		t.Error("Error in LDA zpgX with sero page overflow")
 	}
 
-	s.memory[0x1234] = 0x67
+	s.memory.poke(0x1234, 0x67)
 	executeLine(&s, []uint8{0xAD, 0x34, 0x12})
 	if s.registers.getA() != 0x67 {
 		t.Error("Error in LDA abs")
 	}
 
-	s.memory[0xC057] = 0x7E
+	s.memory.poke(0xC057, 0x7E)
 	s.registers.setX(0x57)
 	executeLine(&s, []uint8{0xBD, 0x00, 0xC0})
 	if s.registers.getA() != 0x7E {
 		t.Error("Error in LDA abs, X")
 	}
 
-	s.memory[0xD059] = 0x7A
+	s.memory.poke(0xD059, 0x7A)
 	s.registers.setY(0x59)
 	executeLine(&s, []uint8{0xB9, 0x00, 0xD0})
 	if s.registers.getA() != 0x7A {
 		t.Error("Error in LDA abs, Y")
 	}
 
-	s.memory[0x24] = 0x74
-	s.memory[0x25] = 0x20
+	s.memory.poke(0x24, 0x74)
+	s.memory.poke(0x25, 0x20)
 	s.registers.setX(0x04)
-	s.memory[0x2074] = 0x66
+	s.memory.poke(0x2074, 0x66)
 	executeLine(&s, []uint8{0xA1, 0x20})
 	if s.registers.getA() != 0x66 {
 		t.Error("Error in LDA (oper,X)")
 	}
 
-	s.memory[0x86] = 0x28
-	s.memory[0x87] = 0x40
+	s.memory.poke(0x86, 0x28)
+	s.memory.poke(0x87, 0x40)
 	s.registers.setY(0x10)
-	s.memory[0x4038] = 0x99
+	s.memory.poke(0x4038, 0x99)
 	executeLine(&s, []uint8{0xB1, 0x86})
 	if s.registers.getA() != 0x99 {
 		t.Error("Error in LDA (oper),Y")
@@ -88,32 +89,33 @@ func TestLoad(t *testing.T) {
 
 func TestStore(t *testing.T) {
 	var s state
+	s.memory.initWithRam()
 	s.registers.setA(0x10)
 	s.registers.setX(0x40)
 	s.registers.setY(0x80)
 
 	executeLine(&s, []uint8{0x85, 0x50})
-	if s.memory[0x0050] != 0x10 {
+	if s.memory.peek(0x0050) != 0x10 {
 		t.Error("Error in STA zpg")
 	}
 
 	executeLine(&s, []uint8{0x86, 0x51})
-	if s.memory[0x0051] != 0x40 {
+	if s.memory.peek(0x0051) != 0x40 {
 		t.Error("Error in STX zpg")
 	}
 
 	executeLine(&s, []uint8{0x84, 0x52})
-	if s.memory[0x0052] != 0x80 {
+	if s.memory.peek(0x0052) != 0x80 {
 		t.Error("Error in STY zpg")
 	}
 
 	executeLine(&s, []uint8{0x8D, 0x20, 0xC0})
-	if s.memory[0xC020] != 0x10 {
+	if s.memory.peek(0xC020) != 0x10 {
 		t.Error("Error in STA abs")
 	}
 
 	executeLine(&s, []uint8{0x9D, 0x08, 0x10})
-	if s.memory[0x1048] != 0x10 {
+	if s.memory.peek(0x1048) != 0x10 {
 		t.Error("Error in STA abs, X")
 	}
 }
@@ -399,23 +401,24 @@ func TestCompare(t *testing.T) {
 }
 func TestBit(t *testing.T) {
 	var s state
+	s.memory.initWithRam()
 
 	s.registers.setA(0x0F)
-	s.memory[0x0040] = 0xF0
+	s.memory.poke(0x0040, 0xF0)
 	executeLine(&s, []uint8{0x24, 0x40})
 	if s.registers.getP() != 0xC2 {
 		t.Errorf("Error in BIT. %v", s.registers)
 	}
 
 	s.registers.setA(0xF0)
-	s.memory[0x0040] = 0xF0
+	s.memory.poke(0x0040, 0xF0)
 	executeLine(&s, []uint8{0x24, 0x40})
 	if s.registers.getP() != 0xC0 {
 		t.Errorf("Error in BIT, 2. %v", s.registers)
 	}
 
 	s.registers.setA(0xF0)
-	s.memory[0x01240] = 0x80
+	s.memory.poke(0x01240, 0x80)
 	executeLine(&s, []uint8{0x2C, 0x40, 0x12})
 	if s.registers.getP() != 0x80 {
 		t.Errorf("Error in BIT, 2. %v", s.registers)
@@ -424,6 +427,7 @@ func TestBit(t *testing.T) {
 
 func TestBranch(t *testing.T) {
 	var s state
+
 	s.registers.setPC(0xC600)
 	s.registers.setFlag(flagV)
 	executeLine(&s, []uint8{0x50, 0x20})
@@ -446,6 +450,7 @@ func TestBranch(t *testing.T) {
 
 func TestStack(t *testing.T) {
 	var s state
+	s.memory.initWithRam()
 
 	s.registers.setSP(0xF0)
 	s.registers.setA(0xA0)
@@ -454,7 +459,7 @@ func TestStack(t *testing.T) {
 	if s.registers.getSP() != 0xEF {
 		t.Errorf("Error in PHA stack pointer, %v", s.registers)
 	}
-	if s.memory[0x01F0] != 0xA0 {
+	if s.memory.peek(0x01F0) != 0xA0 {
 		t.Errorf("Error in PHA, %v", s.registers)
 	}
 
@@ -462,7 +467,7 @@ func TestStack(t *testing.T) {
 	if s.registers.getSP() != 0xEE {
 		t.Errorf("Error in PHP stack pointer, %v", s.registers)
 	}
-	if s.memory[0x01EF] != 0x3A {
+	if s.memory.peek(0x01EF) != 0x3A {
 		t.Errorf("Error in PHP, %v", s.registers)
 	}
 

main.go

@@ -8,7 +8,7 @@ func main() {
 
 	s.registers.setPC(0x0400)
 	for true {
-		testCase := s.memory[0x0200]
+		testCase := s.memory.peek(0x0200)
 		if testCase >= 240 {
 			break
 		}

memory.go

@@ -6,18 +6,62 @@ import (
 	"os"
 )
 
-type memory [65536]uint8
+type memoryPage interface {
+	peek(uint8) uint8
+	poke(uint8, uint8)
+}
+
+type ramPage [256]uint8
+type romPage [256]uint8
+
+type memory [256]memoryPage
+
+func (p *ramPage) peek(address uint8) uint8 {
+	return p[address]
+}
+
+func (p *ramPage) poke(address uint8, value uint8) {
+	p[address] = value
+}
+
+func (p *romPage) peek(address uint8) uint8 {
+	return p[address]
+}
+
+func (p *romPage) poke(address uint8, value uint8) {
+	// Do nothing
+}
+
+func (m *memory) peek(address uint16) uint8 {
+	hi := uint8(address >> 8)
+	lo := uint8(address)
+	return m[hi].peek(lo)
+}
+
+func (m *memory) poke(address uint16, value uint8) {
+	hi := uint8(address >> 8)
+	lo := uint8(address)
+	//fmt.Println(hi)
+	m[hi].poke(lo, value)
+}
 
 func (m *memory) getWord(address uint16) uint16 {
-	return uint16(m[address]) + 0x100*uint16(m[address+1])
+	return uint16(m.peek(address)) + 0x100*uint16(m.peek(address+1))
 }
 
 func (m *memory) getZeroPageWord(address uint8) uint16 {
-	return uint16(m[address]) + 0x100*uint16(m[address+1])
-	// TODO: Does address + 1 wraps around the zero page?
+	return uint16(m.peek(uint16(address))) + 0x100*uint16(m.peek(uint16(address+1)))
+}
+
+func (m *memory) initWithRam() {
+	var ramPages [256]ramPage
+	for i := 0; i < 256; i++ {
+		m[i] = &ramPages[i]
+	}
 }
 
 func (m *memory) loadBinary(filename string) {
+	// Load file
 	f, err := os.Open(filename)
 	if err != nil {
 		panic(err)
@@ -35,8 +79,9 @@ func (m *memory) loadBinary(filename string) {
 	buf := bufio.NewReader(f)
 	buf.Read(bytes)
 
+	m.initWithRam()
 	for i, v := range bytes {
-		m[i] = uint8(v)
+		m.poke(uint16(i), uint8(v))
 	}
 }
 

textPages.go

@@ -0,0 +1,73 @@
+package main
+
+import "fmt"
+
+type textPages struct {
+	dirty bool
+	pages *[4]textPage
+}
+
+type textPage struct {
+	textPages *textPages
+	data      [256]uint8
+}
+
+func (p *textPage) peek(address uint8) uint8 {
+	return p.data[address]
+}
+
+func (p *textPage) poke(address uint8, value uint8) {
+	p.data[address] = value
+	// Note: we could avoid setting dirty on the 16 blocks of 8 hidden bytes
+	p.textPages.dirty = true
+}
+
+func textMemoryByteToString(value uint8) string {
+	return string(value)
+}
+
+func (tp *textPages) dump() {
+	// See "Understand the Apple II", page 5-10
+	// http://www.applelogic.org/files/UNDERSTANDINGTHEAII.pdf
+
+	var i, j, h uint8
+	// Top, middle and botton screen
+	for i = 0; i < 128; i = i + 40 {
+		// Memory pages
+		for _, p := range tp.pages {
+			// The two half pages
+			for _, h = range []uint8{0, 128} {
+				line := ""
+				for j = i + h; j < i+h+40; j++ {
+					line += string(p.peek(j))
+				}
+				fmt.Println(line)
+			}
+		}
+	}
+}
+
+func (tp *textPages) dumpIfDirty() {
+	if !tp.dirty {
+		return
+	}
+
+	tp.dirty = false
+	tp.dump()
+}
+
+func (tp *textPages) charAddress(column uint8, line uint8) (page uint8, address uint8) {
+	page = (line / 3) % 4
+	address = column + (line/8)*40 + (line%2)*128
+	return
+}
+
+func (tp *textPages) read(column uint8, line uint8) uint8 {
+	page, address := tp.charAddress(column, line)
+	return tp.pages[page].peek(address)
+}
+
+func (tp *textPages) write(column uint8, line uint8, value uint8) {
+	page, address := tp.charAddress(column, line)
+	tp.pages[page].poke(address, value)
+}