CBDOS now works in compatibility mode too

src/dos_m65/dos_enter_exit.s

@@ -5,6 +5,10 @@
 
 dos_ENTER:         ; enter DOS context
  
+	php
+	jsr m65_speed_tape_cbdos
+	plp
+
 	sta REG_A
 	stx REG_X
 	sty REG_Y
@@ -26,12 +30,8 @@ dos_EXIT:          ; exit DOS context with Carry clear
 
 dos_EXIT_common:
 
-	ldz REG_Z
-	ldy REG_Y
-	ldx REG_X
 	lda REG_A
-
+	bra dos_EXIT_A_common
-	rts
 
 
 dos_EXIT_A_SEC:    ; exit DOS context with Carry set, return .A
@@ -51,4 +51,8 @@ dos_EXIT_A_common:
 	ldy REG_Y
 	ldx REG_X
 
+	php
+	jsr m65_speed_restore
+	plp
+
 	rts

src/dos_m65/dos_imports.s

@@ -10,3 +10,5 @@
 ;; #ALIAS# kernalstatus_EOI                = KERNAL_0.kernalstatus_EOI
 ;; #ALIAS# kernalstatus_DEVICE_NOT_FOUND   = KERNAL_0.kernalstatus_DEVICE_NOT_FOUND
 
+;; #ALIAS# m65_speed_tape_cbdos            = KERNAL_0.m65_speed_tape_cbdos
+;; #ALIAS# m65_speed_restore               = KERNAL_0.m65_speed_restore

src/dos_m65/dos_init.s

@@ -10,7 +10,12 @@
 
 dos_INIT:
 
-	jsr dos_ENTER
+	; Safer version of 'dos_ENTER' - does not affect speed related registers
+
+	sta REG_A
+	stx REG_X
+	sty REG_Y
+	stz REG_Z
 
 	; Set the magic string 'CBDOS'
 
@@ -60,6 +65,12 @@ dos_INIT:
 	sta code_RTS_03
 	sta code_RTS_04
 
-	; Exit DOS context
+	; Safer version of 'dos_EXIT' - does not affect speed related registers
 
-	jmp dos_EXIT
+	clc
+	ldz REG_Z
+	ldy REG_Y
+	ldx REG_X
+	lda REG_A
+
+	rts

src/kernal/board_m65/mega65_speed.s

@@ -30,13 +30,7 @@ m65_speed_iec:
 
 	; Disable badlines and slow interrupt emulation
 
-	lda #$00
+	bra m65_speed_tape_cbdos_ME
-	sta MISC_EMU
-
-	; Return
-
-	pla
-	rts
 }
 
 
@@ -49,11 +43,22 @@ m65_speed_tape_cbdos:
 	bcc @1
 	jsr viciv_unhide
 @1:
-	; Just set the maximum possible speed
+	; Set the maximum possible speed
 
-	pha
+	lda #%01000000
-	bra m65_speed_restore_native
+	tsb VIC_CTRLB
 
+	; FALLTROUGH
+
+m65_speed_tape_cbdos_ME:
+
+	; Disable badlines and slow interrupt emulation
+
+	lda #$00
+	sta MISC_EMU
+
+	pla
+	rts
 
 
 m65_speed_restore: