Simpler approach for Applecorn trace, no reentrancy

traceApplecorn.go

@@ -2,7 +2,6 @@ package izapple2
 
 import (
 	"fmt"
-	"strings"
 )
 
 /*
@@ -19,18 +18,19 @@ type traceApplecorn struct {
 	a           *Apple2
 	skipConsole bool
 	osbyteNames [256]string
-	calls       []mosCallData
+	call        mosCallData
 	lastDepth   int
+	wasInKernel bool
 }
 
 type mosCallData struct {
-	caller  uint16
 	api     uint16
 	a, x, y uint8
+	skipLog bool
 }
 
 const (
-	applecornMosVec   uint16 = 0xffb9 // Start of the MOS entry points
+	applecornKernelStart uint16 = 0xc000 // Code above this is out of BBC territory
 	applecornNoCaller    uint16 = 0xffff
 )
 
@@ -48,16 +48,17 @@ func newTraceApplecorn(a *Apple2, skipConsole bool) *traceApplecorn {
 	t.osbyteNames[0x85] = "top user mem for mode"
 	t.osbyteNames[0x86] = "read cursor pos"
 	t.osbyteNames[0xDA] = "clear VDU queue"
-	t.calls = make([]mosCallData, 0)
 	return &t
 }
 
 func (t *traceApplecorn) inspect() {
-	pc, sp := t.a.cpu.GetPCAndSP()
-	if pc >= 0xd000 /*applecornMosVec*/ {
-		regA, regX, regY := t.a.cpu.GetAXY()
+	pc, _ := t.a.cpu.GetPCAndSP()
+	inKernel := pc >= applecornKernelStart
 
-		s := ""
+	if !t.wasInKernel && inKernel {
+		regA, regX, regY, _ := t.a.cpu.GetAXYP()
+
+		s := "UNKNOWN"
 		skip := false
 
 		// Page 2 vectors
@@ -123,7 +124,6 @@ func (t *traceApplecorn) inspect() {
 		case 0xffe0:
 			s = fmt.Sprintf("OSRDCH()")
 			skip = t.skipConsole
-			/*
 		case 0xffe3: // This fallbacks to OSWRCH
 			s = "OSASCI(?)"
 			skip = t.skipConsole
@@ -133,7 +133,6 @@ func (t *traceApplecorn) inspect() {
 		case 0xffec: // This fallbacks to OSWRCH
 			skip = t.skipConsole
 			s = fmt.Sprintf("OSNECR()")
-			*/
 		case 0xffee:
 			ch := ""
 			if regA >= 0x20 && regA < 0x7f {
@@ -153,48 +152,42 @@ func (t *traceApplecorn) inspect() {
 			}
 		case 0xfff4:
 			s = fmt.Sprintf("OSBYTE('%s';A=%02x,X=%02x,Y=%02x)", t.osbyteNames[regA], regA, regX, regY)
-			//if regA == 0xda {
-			//	t.a.cpu.Reset()
-			//}
 		case 0xfff7:
 			s = "OSCLI(?)"
 		}
 
-		if !skip && s != "" {
-			caller := t.a.mmu.peekWord(0x100+uint16(sp+1)) + 1
-			t.calls = append(t.calls, mosCallData{caller, pc, regA, regX, regY})
-			if len(t.calls) > t.lastDepth {
-				// Reentrant call, first of block
-				fmt.Println()
-			}
-			if len(t.calls) > 1 {
-				// Reentrant call
-				fmt.Printf("%s", strings.Repeat("  ", len(t.calls)))
-			}
+		t.call.api = pc
+		t.call.a = regA
+		t.call.x = regX
+		t.call.y = regY
+		t.call.skipLog = skip
+		if !skip {
 			fmt.Printf("BBC MOS call to $%04x %s ", pc, s)
-			t.lastDepth = len(t.calls)
 		}
 	}
 
-	if len(t.calls) > 0 && pc == t.calls[len(t.calls)-1].caller {
+	if t.wasInKernel && !inKernel && !t.call.skipLog {
 		// Returning from the call
-		regA, regX, regY := t.a.cpu.GetAXY()
-		call := t.calls[len(t.calls)-1]
+		regA, regX, regY, _ := t.a.cpu.GetAXYP()
 		s := ""
-		switch call.api {
+		switch t.call.api {
 		case 0xfff1: // OSWORD
-			cbAddress := uint16(call.x) + uint16(call.y)<<8
-			switch call.a {
+			cbAddress := uint16(t.call.x) + uint16(t.call.y)<<8
+			switch t.call.a {
 			case 0: // Read line from input
 				lineAddress := t.a.mmu.peekWord(cbAddress)
 				line := t.getString(lineAddress, regY)
 				s = fmt.Sprintf(",line='%s'", line)
+
+				t.a.cpu.SetTrace(true)
+
 			}
 		}
 
 		fmt.Printf("=> (A=%02x,X=%02x,Y=%02x%s)\n", regA, regX, regY, s)
-		t.calls = t.calls[:len(t.calls)-1]
 	}
+
+	t.wasInKernel = inKernel
 }
 
 func (t *traceApplecorn) getString(address uint16, length uint8) string {