Prologue works. OSBYTE76 and OSBYTECA

loadMemory.go

@@ -103,7 +103,7 @@ const (
 	vectorBreak uint16 = 0xfffe
 
 	maxFiles        = 5
-	errorTodo uint8 = 123 // TODO: find proper error number
+	errorTodo uint8 = 129 // TODO: find proper error number
 )
 
 func loadRom(env *environment, filename string) {

osByte.go

@@ -32,6 +32,14 @@ func execOSBYTE(env *environment) {
 		*/
 		// We do nothing
 
+	case 0x76:
+		option = "Reflect keyboard status in keyboard LEDs"
+		/*
+			This call reflects the keyboard status in the state of the keyboard LEDs, and is
+			normally used after the status has been changed by OSBYTE &CA
+		*/
+		// We do nothing
+
 	case 0x7e:
 		option = "Ack detection of an ESC condition"
 		/*
@@ -146,6 +154,21 @@ func execOSBYTE(env *environment) {
 		*/
 		// TODO
 
+	case 0xca:
+		option = "Read/write keyboard status byte"
+		/*
+			The old value is returned in X. The contents of the next location are returned in Y.
+				bit 3: 1 if SHIFT is pressed.
+				bit 4: 0 if CAPS LOCK is engaged.
+				bit 5: 0 if SHIFT LOCK is engaged.
+				bit 6: 1 if CTRL is pressed.
+				bit 7: 1 SHIFT enabled, if a LOCK key is engaged then SHIFT reverses the LOCK.
+
+			We return 0 always
+		*/
+		newX = 0
+		newY = 0
+
 	case 0xda:
 		option = "R/W number of items in VDU"
 		/*

osFind.go

@@ -43,11 +43,13 @@ func execOSFIND(env *environment) {
 		if y == 0 {
 			// Close all files
 			for i := 0; i < maxFiles; i++ {
-				err := env.file[i].Close()
-				if err != nil {
-					env.raiseError(errorTodo, err.Error())
+				if env.file[i] != nil {
+					err := env.file[i].Close()
+					if err != nil {
+						env.raiseError(errorTodo, err.Error())
+					}
+					env.file[i] = nil
 				}
-				env.file[i] = nil
 			}
 			env.log("OSFIND('Close all files')")
 		} else {