Updated the quiet-flag to be more logical (#137)

Now the quiet flag behaves in a more predictable way, being 1 when quiet mode is active - rather than zero. This closes #136
skx · Jun 24, 2024 · 0333b9b · 0333b9b
1 parent 180ca09
commit 0333b9b
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Showing 4 changed files with 43 additions and 43 deletions.
diff --git a/EXTENSIONS.md b/EXTENSIONS.md
@@ -73,13 +73,13 @@ Demonstrated in [samples/ccp.z80](samples/ccp.z80)
 
 
 
-## Function 0x04: Get/Set Quiet
+## Function 0x04: Get/Set Quiet Flag
 
-* If C is 0x00 quiet-mode is enabled.
-* If C is 0x01 quiet-mode is disabled.
+* If C is 0x01 quiet-mode is enabled.
+* If C is 0x00 quiet-mode is disabled.
 * If C is 0xFF quiet-mode is queried.
-   * 0x00 means it is active
-   * 0x01 means it is not active.
+   * 0x00 means it is disabled.
+   * 0x01 means it is active
 
 Quiet mode prevents the display of a banner every time the CCP is restarted.
 

diff --git a/cpm/cpm_bios.go b/cpm/cpm_bios.go
@@ -138,16 +138,7 @@ func BiosSysCallReserved1(cpm *CPM) error {
 	// HL == 1
 	//    C == 0xff to get the ctrl-c count
 	//    C != 0xff to set the ctrl-c count
-	//
-	// HL == 2
-	//    DE points to a string containing the console driver to use.
-	//
-	// HL == 3
-	//    DE points to a string containing the CCP to use.
-	//
-	// HL == 4
-	//    C == 0 - Quiet mode on.
-	//    C != 0 - Quiet mode off
+	// ...
 	//
 	hl := cpm.CPU.States.HL.U16()
 	c := cpm.CPU.States.BC.Lo
@@ -157,8 +148,8 @@ func BiosSysCallReserved1(cpm *CPM) error {
 	// Helper to read a null/space terminated string from
 	// memory.
 	//
-	// Here because our custom syscalls read a string when
-	// setting both CCP and DisplayDriver.
+	// Here because several of our custom syscalls need to
+	// read a string from the caller.
 	//
 	getStringFromMemory := func(addr uint16) string {
 		str := ""
@@ -176,6 +167,7 @@ func BiosSysCallReserved1(cpm *CPM) error {
 
 	switch hl {
 
+	// Is this a CPMUlator?
 	case 0x0000:
 		// Magic values in the registers
 		cpm.CPU.States.HL.Hi = 'S'
@@ -200,13 +192,15 @@ func BiosSysCallReserved1(cpm *CPM) error {
 		}
 		return nil
 
+	// Get/Set the ctrl-c flag
 	case 0x0001:
 		if c == 0xFF {
 			cpm.CPU.States.AF.Hi = uint8(cpm.input.GetInterruptCount())
 		} else {
 			cpm.input.SetInterruptCount(int(c))
 		}
 
+	// Get/Set the console driver.
 	case 0x0002:
 
 		if de == 0x0000 {
@@ -254,6 +248,7 @@ func BiosSysCallReserved1(cpm *CPM) error {
 			fmt.Printf("Console driver is already %s, making no change.\n", str)
 		}
 
+	// Get/Set the CCP
 	case 0x0003:
 
 		if de == 0x0000 {
@@ -299,30 +294,34 @@ func BiosSysCallReserved1(cpm *CPM) error {
 			fmt.Printf("CCP is already %s, making no change.\n", str)
 		}
 
+	// Get/Set the quiet flag
 	case 0x0004:
 
 		// if C == 00
+		//   Set the quiet flag to be false
+		//
+		// if C == 01
 		//   Set the quiet flag to be true
 		//
 		// If C == 0xFF
-		//   Return the statues of the flag in C (0 = quiet, 1 = non-quiet)
-		//
-		// Set the quiet flag
+		//   Return the statues of the flag in C
+		//   (1 = quiet, 0 = non-quiet)
+
 		if c == 0x00 {
-			cpm.SetQuiet(true)
+			cpm.SetQuiet(false)
 		}
 		if c == 0x01 {
-			cpm.SetQuiet(false)
+			cpm.SetQuiet(true)
 		}
 		if c == 0xFF {
 			if cpm.GetQuiet() {
-				cpm.CPU.States.BC.Lo = 0x00
-			} else {
 				cpm.CPU.States.BC.Lo = 0x01
+			} else {
+				cpm.CPU.States.BC.Lo = 0x00
 			}
-
 		}
 
+	// Get terminal size in HL
 	case 0x0005:
 		width, height, err := term.GetSize(int(os.Stdin.Fd()))
 		if err != nil {

diff --git a/static/A/QUIET.COM b/static/A/QUIET.COM
diff --git a/static/quiet.z80 b/static/quiet.z80
@@ -44,22 +44,28 @@ BDOS_OUTPUT_STRING:   EQU 9
         cp '1'
         jr z, set_quiet
         cp '0'
-        jr z, set_non_quiet
+        jr z, unset_quiet
+
+        ;; unknown argument
+        LD DE, WRONG_ARGUMENT
+        LD C, BDOS_OUTPUT_STRING
+        call BDOS_ENTRY_POINT
+        jr exit
 
-        jr unknown_argument
 
 
-set_non_quiet:
+set_quiet:
         ld c, 0x01
         jr set_quiet_middle
 
-set_quiet:
+unset_quiet:
         ld  c, 0x00
 set_quiet_middle:
         ld HL, 0x04
         ld  a, 31
         out (0xff), a
-        jr exit
+
+        ;; fall-through
 
 ;; get the value of the quiet flag
 show_value:
@@ -70,10 +76,15 @@ show_value:
 
         ld a,c
         cp 0x00
-        jr z,show_quiet_on
+        jr z,show_quiet_off
         cp 0x01
-        jr z, show_quiet_off
-        jr show_quiet_wtf
+        jr z, show_quiet_on
+        ;; fall-through
+
+        LD DE, QUIET_MODE_UNKNOWN
+        LD C, BDOS_OUTPUT_STRING
+        call BDOS_ENTRY_POINT
+        ;; fall-through
 
         ;; Exit
 exit:
@@ -93,20 +104,10 @@ show_quiet_on:
         call BDOS_ENTRY_POINT
         jr exit
 
-show_quiet_wtf:
-        LD DE, QUIET_MODE_UNKNOWN
-        LD C, BDOS_OUTPUT_STRING
-        call BDOS_ENTRY_POINT
-        jr exit
 
 ;;
 ;; Error Routines
 ;;
-unknown_argument:
-        LD DE, WRONG_ARGUMENT
-        LD C, BDOS_OUTPUT_STRING
-        call BDOS_ENTRY_POINT
-        jr exit
 
 not_cpmulator:
         LD DE, WRONG_EMULATOR