Support for FLASH and INVERSE. Extract text display code to the ANSI frontend

apple2/ansiConsoleFrontend.go

@@ -2,34 +2,43 @@ package apple2
 
 import (
 	"bufio"
+	"fmt"
 	"os"
+	"strings"
+	"time"
 )
 
 type ansiConsoleFrontend struct {
-	keyChannel chan uint8
+	keyChannel     chan uint8
+	extraLineFeeds chan int
 }
 
-func _stdinReader(c chan uint8) {
-	reader := bufio.NewReader(os.Stdin)
-	for {
-		byte, err := reader.ReadByte()
-		if err != nil {
-			panic(err)
-		}
-		c <- byte
-	}
-}
+const refreshDelayMs = 100
 
 func (fe *ansiConsoleFrontend) getKey() (key uint8, ok bool) {
+	stdinReader := func(c chan uint8) {
+		reader := bufio.NewReader(os.Stdin)
+		for {
+			byte, err := reader.ReadByte()
+			if err != nil {
+				panic(err)
+			}
+			c <- byte
+		}
+	}
+
 	if fe.keyChannel == nil {
 		fe.keyChannel = make(chan uint8, 100)
-		go _stdinReader(fe.keyChannel)
+		go stdinReader(fe.keyChannel)
 	}
 
 	select {
 	case key = <-fe.keyChannel:
 		if key == 10 {
 			key = 13
+			if fe.extraLineFeeds != nil {
+				fe.extraLineFeeds <- 1
+			}
 		}
 		ok = true
 	default:
@@ -37,3 +46,82 @@ func (fe *ansiConsoleFrontend) getKey() (key uint8, ok bool) {
 	}
 	return
 }
+
+func ansiCursorUp(steps int) {
+	fmt.Printf("\033[%vA", steps)
+}
+
+func (fe *ansiConsoleFrontend) textModeGoRoutine(tp *textPages) {
+	fe.extraLineFeeds = make(chan int, 100)
+
+	fmt.Printf(strings.Repeat("\n", 26))
+	for {
+		if tp.strobe() {
+			// Go up
+			ansiCursorUp(26)
+			done := false
+			for !done {
+				select {
+				case lineFeeds := <-fe.extraLineFeeds:
+					ansiCursorUp(lineFeeds)
+				default:
+					done = true
+				}
+			}
+
+			fmt.Println(strings.Repeat("#", 44))
+
+			// 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 < 120; 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 += textMemoryByteToString(p.Peek(j))
+						}
+						fmt.Printf("# %v #\n", line)
+					}
+				}
+			}
+
+			fmt.Println(strings.Repeat("#", 44))
+			fmt.Print("\033[KLine: ")
+
+		}
+		time.Sleep(refreshDelayMs * time.Millisecond)
+	}
+}
+
+func textMemoryByteToString(value uint8) string {
+	// See https://en.wikipedia.org/wiki/Apple_II_character_set
+	// Only ascii from 0x20 to 0x5F is visible
+	topBits := value >> 6
+	isInverse := topBits == 0
+	isFlash := topBits == 1
+
+	value = (value & 0x3F)
+	if value < 0x20 {
+		value += 0x40
+	}
+
+	if isFlash {
+		if value == ' ' {
+			// Flashing space in Apple is the full box. It can't be done with ANSI codes
+			value = '_'
+		}
+		return fmt.Sprintf("\033[5m%v\033[0m", string(value))
+	} else if isInverse {
+		return fmt.Sprintf("\033[7m%v\033[0m", string(value))
+	} else {
+		return string(value)
+	}
+}
+
+func textMemoryByteToStringHex(value uint8) string {
+	return fmt.Sprintf("%02x ", value)
+}

apple2/apple2.go

@@ -18,12 +18,11 @@ func Run(romFile string, log bool) {
 
 	var fe ansiConsoleFrontend
 	io.setKeyboardProvider(&fe)
+	go fe.textModeGoRoutine(&t)
 
 	// Start the processor
 	core6502.Reset(&s)
-	t.prepare()
 	for {
 		core6502.ExecuteInstruction(&s, log)
-		t.dumpIfDirty()
 	}
 }

apple2/textPages.go

@@ -1,13 +1,7 @@
 package apple2
 
-import (
-	"fmt"
-	"time"
-)
-
 type textPages struct {
-	lastDump int64
-	pages    [4]textPage
+	pages [4]textPage
 }
 
 type textPage struct {
@@ -25,80 +19,6 @@ func (p *textPage) Poke(address uint8, value uint8) {
 	p.dirty = true
 }
 
-func textMemoryByteToString(value uint8) string {
-	value = value & 0x7F
-	if value < ' ' {
-		return "@"
-	}
-
-	return string(value)
-}
-
-func textMemoryByteToStringHex(value uint8) string {
-	return fmt.Sprintf("%02x ", value)
-}
-
-func (tp *textPages) prepare() {
-	fmt.Printf("\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n")
-}
-
-func (tp *textPages) dump() {
-	// See "Understand the Apple II", page 5-10
-	// http://www.applelogic.org/files/UNDERSTANDINGTHEAII.pdf
-
-	fmt.Print("\033[26A")
-
-	fmt.Println("------------------------------------------")
-
-	var i, j, h uint8
-	// Top, middle and botton screen
-	for i = 0; i < 120; 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 += textMemoryByteToString(p.Peek(j))
-				}
-				fmt.Printf("| %v |\n", line)
-			}
-		}
-	}
-
-	fmt.Println("------------------------------------------")
-	tp.lastDump = time.Now().UnixNano()
-
-}
-
-const refreshDelayMs = 100
-
-func (tp *textPages) dumpIfDirty() {
-	if time.Now().UnixNano()-tp.lastDump < refreshDelayMs*1000*1000 {
-		// Wait more the next refresh
-		return
-	}
-
-	dirty := false
-	for i := 0; i < 4; i++ {
-		if tp.pages[i].dirty {
-			dirty = true
-			tp.pages[i].dirty = false
-		}
-	}
-
-	if !dirty {
-		return
-	}
-	tp.dump()
-}
-
-func (tp *textPages) charAddress(column uint8, line uint8) (page uint8, address uint8) {
-	page = (line % 8) / 2
-	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)
@@ -108,3 +28,21 @@ func (tp *textPages) write(column uint8, line uint8, value uint8) {
 	page, address := tp.charAddress(column, line)
 	tp.pages[page].Poke(address, value)
 }
+
+func (tp *textPages) charAddress(column uint8, line uint8) (page uint8, address uint8) {
+	page = (line % 8) / 2
+	address = column + (line/8)*40 + (line%2)*128
+	return
+}
+
+func (tp *textPages) strobe() bool {
+	// Thread safe. May just mark more dirties than needed.
+	dirty := false
+	for i := 0; i < 4; i++ {
+		if tp.pages[i].dirty {
+			dirty = true
+			tp.pages[i].dirty = false
+		}
+	}
+	return dirty
+}