+;
+; Marco van den Heuvel, 2018-04-25
+;
+
+; extern unsigned char __fastcall__ set_chameleon_speed (unsigned char speed);
+;
+;/* Set the speed of the Chameleon cartridge, the following inputs
+; * are accepted:
+; * SPEED_SLOW : 1 Mhz mode
+; * SPEED_1X : 1 Mhz mode
+; * SPEED_2X : 2 Mhz mode
+; * SPEED_3X : 3 Mhz mode
+; * SPEED_4X : 4 Mhz mode
+; * SPEED_5X : 5 Mhz mode
+; * SPEED_6X : 6 Mhz mode
+; * SPEED_FAST : Maximum speed mode
+; *
+; * Note that any value higher or equal to SPEED_7X will switch to maximum
+; * speed mode.
+; *
+; * This function will return the actual speed the CPU is at after trying
+; * to set the requested speed, to my knowledge the switching should not fail.
+; *
+; * This function does not check for the presence of the Chameleon cartridge,
+; * make sure you use 'detect_chameleon();' before using.
+; */
+
+; extern unsigned char get_chameleon_speed (void);
+;
+;/* Get the speed of the Chameleon cartridge.
+; *
+; * Possible return values:
+; * SPEED_SLOW : Slow mode
+; * SPEED_2X : 2Mhz mode
+; * SPEED_3X : 3Mhz mode
+; * SPEED_4X : 4Mhz mode
+; * SPEED_5X : 5Mhz mode
+; * SPEED_6X : 6Mhz mode
+; * SPEED_FAST : Maximum speed mode
+; *
+; * This function does not check for the presence of the Chameleon cartridge,
+; * make sure you use 'detect_chameleon();' before using.
+; */
+
+ .export _set_chameleon_speed
+ .export _get_chameleon_speed
+
+ .include "accelerator.inc"
+
+_set_chameleon_speed:
+ cmp #SPEED_7X
+ bcs maximum_speed
+ cmp #SPEED_1X
+ beq low_speed
+ ora #$80
+set_speed:
+ jsr activate_regs
+ sta CHAMELEON_CFGTUR
+ jmp return_speed
+
+low_speed:
+ lda #CHAMELEON_CFGTUR_LIMIT_1MHZ
+ bne set_speed
+
+maximum_speed:
+ lda #CHAMELEON_CFGTUR_LIMIT_NONE
+ bne set_speed
+
+_get_chameleon_speed:
+ jsr activate_regs
+return_speed:
+ ldx #$00
+ lda CHAMELEON_CFGTUR
+ tay
+ and #%10000000
+ beq return_value
+ tya
+ and #%00001000
+ bne is_slow_mode
+ tya
+ and #%00000111
+ beq is_max_mode
+return_value:
+ ldy #CHAMELEON_DISABLE_REGS
+ sty CHAMELEON_CFGENA
+ rts
+
+is_slow_mode:
+ txa
+ bne return_value
+
+is_max_mode:
+ lda #SPEED_FAST
+ bne return_value
+
+activate_regs:
+ ldy #CHAMELEON_ENABLE_REGS
+ sty CHAMELEON_CFGENA
+ rts
+