Trace calls to the BBC MOS when using Applecorn

README.md

@@ -60,6 +60,7 @@ Portable emulator of an Apple II+ or //e. Written in Go.
   - ProDOS MLI calls
   - Apple Pascal BIOS calls
   - Smartport commands
+  - BBC MOS calls when using [Applecorn](https://github.com/bobbimanners/)
 - Other features:
   - Sound
   - Joystick support. Up to two joysticks or four paddles
@@ -227,6 +228,10 @@ Only valid on SDL mode
         use the sequencer based Disk II card
   -thunderClockCardSlot int
         slot for the ThunderClock Plus card. -1 for none (default 4)
+  -traceBBC
+        trace BBC MOS API calls used with Applecorn, skip console I/O calls
+  -traceBBCFull
+        trace BBC MOS API calls used with Applecorn
   -traceCpu
         dump to the console the CPU execution. Use F11 to toggle.
   -traceHD

apple2main.go

@@ -142,6 +142,14 @@ func MainApple() *Apple2 {
 		"sequencer",
 		false,
 		"use the sequencer based Disk II card")
+	traceBBC := flag.Bool(
+		"traceBBC",
+		false,
+		"trace BBC MOS API calls used with Applecorn, skip console I/O calls")
+	traceBBCFull := flag.Bool(
+		"traceBBCFull",
+		false,
+		"trace BBC MOS API calls used with Applecorn")
 
 	flag.Parse()
 
@@ -170,6 +178,12 @@ func MainApple() *Apple2 {
 	if *tracePascal {
 		a.addTracer(newTracePascal(a))
 	}
+	if *traceBBC {
+		a.addTracer(newTraceApplecorn(a, false))
+	}
+	if *traceBBCFull {
+		a.addTracer(newTraceApplecorn(a, true))
+	}
 
 	var charGenMap charColumnMap
 	initialCharGenPage := 0

core6502/execute.go

@@ -127,11 +127,16 @@ func (s *State) GetPCAndSP() (uint16, uint8) {
 	return s.reg.getPC(), s.reg.getSP()
 }
 
-// GetCarryAndAcc returns the value of te carry flag and the accumulator. Used to trace MLI calls
+// GetCarryAndAcc returns the value of the carry flag and the accumulator. Used to trace MLI calls
 func (s *State) GetCarryAndAcc() (bool, uint8) {
 	return s.reg.getFlag(flagC), s.reg.getA()
 }
 
+// GetAXY returns the value of the A, X and Y registers
+func (s *State) GetAXY() (uint8, uint8, uint8) {
+	return s.reg.getA(), s.reg.getX(), s.reg.getY()
+}
+
 // Save saves the CPU state (registers and cycle counter)
 func (s *State) Save(w io.Writer) error {
 	err := binary.Write(w, binary.BigEndian, s.cycles)

traceApplecorn.go

@@ -0,0 +1,107 @@
+package izapple2
+
+import "fmt"
+
+/*
+  See:
+    https://github.com/bobbimanners/Applecorn
+	http://beebwiki.mdfs.net/Category:MOS_API
+	http://beebwiki.mdfs.net/OSBYTEs
+	http://mdfs.net/Docs/Comp/BBC/Osbyte00
+
+*/
+
+type traceApplecorn struct {
+	a           *Apple2
+	skipConsole bool
+	osbyteNames [256]string
+}
+
+const (
+	applecornMosVec uint16 = 0xffb9 // Start of the MOS entry points
+)
+
+func newTraceApplecorn(a *Apple2, skipConsole bool) *traceApplecorn {
+	var t traceApplecorn
+	t.a = a
+	t.skipConsole = skipConsole
+	t.osbyteNames[0x7c] = "clear escape condition"
+	t.osbyteNames[0x7d] = "set escape condition"
+	t.osbyteNames[0x7e] = "ack detection of ESC"
+	t.osbyteNames[0x81] = "Read key with time lim"
+	t.osbyteNames[0x82] = "read high order address"
+	t.osbyteNames[0x83] = "read bottom of user mem"
+	t.osbyteNames[0x84] = "read top of user mem"
+	t.osbyteNames[0x85] = "top user mem for mode"
+	t.osbyteNames[0x86] = "read cursor pos"
+	t.osbyteNames[0xDA] = "clear VDU queue"
+
+	return &t
+}
+
+func (t *traceApplecorn) inspect() {
+	pc, _ := t.a.cpu.GetPCAndSP()
+	if pc >= applecornMosVec {
+		regA, regX, regY := t.a.cpu.GetAXY()
+		s := ""
+
+		if !t.skipConsole {
+			switch pc {
+			case 0xffe0:
+				s = fmt.Sprintf("OSNEWL()")
+			case 0xffc8:
+				ch := ""
+				if regA >= 0x20 && regA < 0x7f {
+					ch = string(regA)
+				}
+				s = fmt.Sprintf("OSNWRCH(A=%02x, '%v')", regA, ch)
+			case 0xffcb:
+				s = fmt.Sprintf("OSNRDCH()")
+			case 0xffe7:
+				s = fmt.Sprintf("OSRDCH()")
+			case 0xffee:
+				ch := ""
+				if regA >= 0x20 && regA < 0x7f {
+					ch = string(regA)
+				}
+				s = fmt.Sprintf("OSWRCH(A=%02x, '%v')", regA, ch)
+			}
+
+		}
+
+		switch pc {
+		case 0xffb9:
+			s = "OSDRM(?)"
+		case 0xffbf:
+			s = "OSEVEN(?)"
+		case 0xffc2:
+			s = "OSINIT(?)"
+		case 0xffc5:
+			s = "OSREAD(?)"
+		case 0xffce:
+			s = "OSFIND(?)"
+		case 0xffd1:
+			s = "OSGBPB(?)"
+		case 0xffd4:
+			s = "OSBPUT(?)"
+		case 0xffd7:
+			s = "OSBGET(?)"
+		case 0xffda:
+			s = "OSARGS(?)"
+		case 0xffdd:
+			s = "OSFILE(?)"
+		case 0xffe3:
+			s = "OSASCI(?)"
+		case 0xfff1:
+			s = fmt.Sprintf("OSWORD(A=%02x,XY=%04x)", regA, uint16(regX)<<8+uint16(regY))
+		case 0xfff4:
+			s = fmt.Sprintf("OSBYTE('%s';A=%02x,X=%02x,Y=%02x)", t.osbyteNames[regA], regA, regX, regY)
+		case 0xfff7:
+			s = "OSCLI(?)"
+		}
+
+		if s != "" {
+			fmt.Printf("BBC MOS call to $%04x %s\n", pc, s)
+		}
+	}
+}