Added $SIMPLE_CHAR to disable the output rewriting

README.md

@@ -186,10 +186,11 @@ The console-I/O is blocking by default, but that can be changed by setting the e
 
 Here is the complete list of environmental variables which influence behaviour:
 
-| Variable  | Purpose                                                       |
-|-----------|---------------------------------------------------------------|
-| DEBUG     | Send a log of CP/M syscalls to STDERR                         |
-| NON_BLOCK | Avoid blocking for console input, instead poll in a busy-loop |
+| Variable    | Purpose                                                       |
+|-------------|---------------------------------------------------------------|
+| DEBUG       | Send a log of CP/M syscalls to STDERR                         |
+| NON_BLOCK   | Avoid blocking for console input, instead poll in a busy-loop |
+| SIMPLE_CHAR | Avoid the attempted VT52 output conversion.                   |
 
 
 

cpm/cpm_syscalls.go

@@ -115,6 +115,12 @@ func SysCallAuxWrite(cpm *CPM) error {
 //
 // This is all a bit sleazy.
 func (cpm *CPM) outC(c uint8) {
+
+	if os.Getenv("SIMPLE_CHAR") != "" {
+		fmt.Printf("%c", c)
+		return
+	}
+
 	switch cpm.auxStatus {
 	case 0:
 		switch c {
@@ -281,7 +287,7 @@ func SysCallRawIO(cpm *CPM) error {
 		}
 		return nil
 	default:
-		fmt.Printf("%c", 0x7f&cpm.CPU.States.DE.Lo)
+		cpm.outC(cpm.CPU.States.DE.Lo)
 	}
 	return nil
 }