--- a/src/divemenu_tree.asm	Fri Feb 21 10:51:36 2020 +0100
+++ b/src/divemenu_tree.asm	Fri Feb 28 15:45:07 2020 +0100
@@ -1,6 +1,6 @@
 ;=============================================================================
 ;
-;   File divemenu_tree.asm                    combined next generation V3.03.4
+;   File divemenu_tree.asm                    combined next generation V3.08.8
 ;
 ;   OSTC dive mode menu
 ;
@@ -25,7 +25,9 @@
 dmenu_tree	CODE
 
 ;=============================================================================
-; Main Menu
+;
+; Dive Mode Menu
+;
 
 do_return_main_divemenu:
 	call	menu_processor_double_pop	; drop exit line and back to last line
@@ -35,9 +37,10 @@
 
 	global	do_main_divemenu
 do_main_divemenu:
-	call	menu_processor_reset		; restart from first icon
-	movlw	.1
-	movwf	menu_pos_cur				; set to first option in dive mode menu
+	movff	active_customview,backup_customview	; back up current custom view
+	call	menu_processor_reset				; restart from first icon
+	movlw	.1									; set cursor to first menu item
+	movwf	menu_pos_cur						; ...
 
 do_main_divemenu_common:
  IFDEF _ccr_pscr
@@ -54,28 +57,31 @@
  ENDIF
 
  IFDEF _cave_mode
-	btfss	cave_mode					; in cave mode?
-	bra		main_divemenu_OC_no_cave	; NO - do OC menu without turn option
+	TSTOSS	opt_cave_mode				; cave mode switched on?
+	bra		main_divemenu_OC_nocave		; NO  - use version without cave mode entry
+	;bra	main_divemenu_OC_cave		; YES - use version with    cave mode entry
 
+main_divemenu_OC_cave:
 	MENU_BEGIN	tMainMenu,	.6
 		MENU_CALL		tDivemenu_Gaslist,	do_divemode_gaslist
 		MENU_CALL		tDivemenu_ResetAvg,	do_reset_average
-		MENU_DYNAMIC	do_toggle_gf_label,	do_toggle_gf
+		MENU_DYNAMIC	label_do_toggle_gf,	do_toggle_gf
 		MENU_CALL		tDivemenu_Marker,	do_set_marker
-		MENU_DYNAMIC	do_turn_dive_label,	do_turn_dive
+		MENU_CALL		tCaveMode,			do_main_cavemenu
 		MENU_CALL		tExit,				do_exit_divemode_menu
 	MENU_END
  ENDIF
 
-main_divemenu_OC_no_cave:
+main_divemenu_OC_nocave:
 	MENU_BEGIN	tMainMenu,	.5
 		MENU_CALL		tDivemenu_Gaslist,	do_divemode_gaslist
 		MENU_CALL		tDivemenu_ResetAvg,	do_reset_average
-		MENU_DYNAMIC	do_toggle_gf_label,	do_toggle_gf
+		MENU_DYNAMIC	label_do_toggle_gf,	do_toggle_gf
 		MENU_CALL		tDivemenu_Marker,	do_set_marker
 		MENU_CALL		tExit,				do_exit_divemode_menu
 	MENU_END
 
+
 ;=============================================================================
 
  IFDEF _ccr_pscr
@@ -83,26 +89,25 @@
 main_divemenu_loop:
 	bsf		is_diluent_menu				; selecting diluents ...
 	bcf		is_bailout_menu				; ... (definitely) not for bailout reason
-	btfsc	FLAG_pscr_mode
-	bra		main_divemenu_pscr			; pSCR menu
+	btfsc	FLAG_pscr_mode				; in pSCR mode?
+	bra		main_divemenu_pscr			; YES - show pSCR menu
 
 	MENU_BEGIN	tMainMenu,	.6
 		MENU_CALL		tDiveBailout,		do_divemode_gaslist_bail
 		MENU_CALL		tDivemenu_Setpoint,	do_divemode_splist
 		MENU_CALL		tDivemenu_Diluent,	do_divemode_gaslist
 		MENU_CALL		tDivemenu_Avg_Mkr,	do_reset_avg_set_mkr
-		MENU_DYNAMIC	do_toggle_gf_label,	do_toggle_gf
+		MENU_DYNAMIC	label_do_toggle_gf,	do_toggle_gf
 		MENU_CALL		tExit,				do_exit_divemode_menu
 	MENU_END
 
 
 main_divemenu_pscr:
-
  IFDEF _external_sensor
 	btfsc	analog_o2_input				; do we have an analog  input (OSTC cR)?
-	bra		main_divemenu_pscr_sensors	; YES
+	bra		main_divemenu_pscr_sensors	; YES - do menu with calibration
 	btfsc	optical_input				; do we have an optical input (OSTC 3)?
-	bra		main_divemenu_pscr_sensors	; YES
+	bra		main_divemenu_pscr_sensors	; YES - do menu with calibration
  ENDIF
 
 main_divemenu_pscr_no_sensors:
@@ -111,19 +116,18 @@
 		MENU_CALL		tDivemenu_Premix,	do_divemode_gaslist
 		MENU_CALL		tBackToLoop,		do_switch_sp_calc
 		MENU_CALL		tDivemenu_Avg_Mkr,	do_reset_avg_set_mkr
-		MENU_DYNAMIC	do_toggle_gf_label,	do_toggle_gf
+		MENU_DYNAMIC	label_do_toggle_gf,	do_toggle_gf
 		MENU_CALL		tExit,				do_exit_divemode_menu
 	MENU_END
 
-
+main_divemenu_pscr_sensors:
  IFDEF _external_sensor
-main_divemenu_pscr_sensors:
 	MENU_BEGIN	tMainMenu,	.6
 		MENU_CALL		tDiveBailout,		do_divemode_gaslist_bail
 		MENU_CALL		tCCRSensor,			do_divemode_setpoint_pscr
 		MENU_CALL		tDivemenu_Premix,	do_divemode_gaslist
 		MENU_CALL		tDivemenu_Avg_Mkr,	do_reset_avg_set_mkr
-		MENU_DYNAMIC	do_toggle_gf_label,	do_toggle_gf
+		MENU_DYNAMIC	label_do_toggle_gf,	do_toggle_gf
 		MENU_CALL		tExit,				do_exit_divemode_menu
 	MENU_END
  ENDIF	; _external_sensor
@@ -132,44 +136,51 @@
 
 ;=============================================================================
 
+
+do_return_toggle_gf:
+	call	menu_processor_pop			; drop selection from menu stack
+	bra		do_toggle_gf_1				; re-draw the custom view and enter the menu again
+
 do_toggle_gf:
-	TSTOSS	char_I_deco_model			; toggle GF only in GF modes - in GF mode? (0 = ZH-L16, 1 = ZH-L16-GF)
+	TSTOSS	char_I_model				; toggle GF only in GF modes - in GF mode? (0 = ZH-L16, 1 = ZH-L16-GF)
 	bra		do_main_divemenu_common		; NO - do nothing and return
 	TSTOSS	opt_enable_aGF				; =1: aGF can be selected underwater
 	bra		do_main_divemenu_common		; NO - do nothing and return
-	movlw	index_gf_factors-1			; custom view number one below GF factors
-	movwf	active_customview			; set custom view number
-	bsf		request_next_custview		; initiate toggle to desired custom view -> GF factors
-	movlw	.1
-	movwf	menu_pos_cur				; set to first option in dive mode menu
+	bsf		custom_view_locked			; lock custom view
+do_toggle_gf_1:
+	movlw	index_gf_factors			; get  number of GF factors custom view
+	movwf	active_customview			; set  custom view number
+	call	dive_customview_callup		; draw custom view
+	movlw	.1							; set to first option in dive mode menu
+	movwf	menu_pos_cur				; ...
 
 	MENU_BEGIN	tDivemenu_ToggleGF,	.2
-		MENU_CALL		tDivemenu_ToggleGF,	do_togglegf
-		MENU_CALL		tBack,				do_return_main_divemenu
+		MENU_CALL		tDivemenu_ToggleGF,	do_toggle_gf_toggle
+		MENU_CALL		tExit,				do_exit_divemode_menu
 	MENU_END
 
-do_togglegf:
-	bsf		request_toggle_GF			; set request flag
-	bra		do_exit_divemode_menu		; continue with exiting menu code
+do_toggle_gf_toggle:
+	bsf		request_toggle_GF			; set request flag to have the deco engine restarted
+	btg		use_aGF						; toggle normal / alternative GF factor selection
+	btfsc	use_aGF						; alternative GF factors activated?
+	bra		do_togglegf_agf				; YES - branch to using alternative GF
+	;bra	do_togglegf_ngf				; NO  - branch to using normal      GF
+
+do_togglegf_ngf:
+	movff	opt_GF_low, char_I_GF_Low_percentage	; use normal GF factor low
+	movff	opt_GF_high,char_I_GF_High_percentage	; use normal GF factor high
+	bra		do_return_toggle_gf						; back to menu
+
+do_togglegf_agf:
+	movff	opt_aGF_low, char_I_GF_Low_percentage	; use alternative GF factor low
+	movff	opt_aGF_high,char_I_GF_High_percentage	; use alternative GF factor high
+	bra		do_return_toggle_gf						; back to menu
 
 
 do_reset_avg_set_mkr:
-	movlw	.1
-	movwf	menu_pos_cur				; set to first option in dive mode menu
-
- IFDEF _cave_mode
-	btfss	cave_mode					; in cave mode?
-	bra		do_reset_average_no_cave	; NO - do menu without turn option
+	movlw	.1							; set to first option in dive mode menu
+	movwf	menu_pos_cur				; ...
 
-	MENU_BEGIN	tDivemenu_Avg_Mkr,	.4
-		MENU_CALL		tDivemenu_ResetAvg,	do_reset_average
-		MENU_CALL		tDivemenu_Marker,	do_set_marker
-		MENU_DYNAMIC	do_turn_dive_label,	do_turn_dive
-		MENU_CALL		tBack,				do_return_main_divemenu
-	MENU_END
- ENDIF
-
-do_reset_average_no_cave:
 	MENU_BEGIN	tDivemenu_Avg_Mkr,	.3
 		MENU_CALL		tDivemenu_ResetAvg,	do_reset_average
 		MENU_CALL		tDivemenu_Marker,	do_set_marker
@@ -182,27 +193,12 @@
  IFDEF _min_depth_option
 	bsf		reset_trip_pressure			; request ISR to reset the min and max trip-wise pressures
  ENDIF
-	bra		do_exit_divemode_menu		; exit
+	bra		do_exit_divemode_menu		; continue exiting the menu
 
 
 do_set_marker:
 	bsf		request_set_marker			; set request flag
-	bra		do_exit_divemode_menu		; exit
-
-
- IFDEF _cave_mode
-do_turn_dive:
-	bsf		request_turn_dive			; set request flag
-	bra		do_exit_divemode_menu		; exit
- ENDIF
-
-
- IFDEF _external_sensor
-do_switch_sensor:						; entry point when coming from switch to sensor
-	movlw	.1							; switch to sensor
-	movff	WREG,opt_ccr_mode			; =0: fixed SP (CCR) / calculated (pSCR), =1: Sensor, =2: Auto SP
-	bra		do_switch_sp_com			; continue with common part
- ENDIF
+	bra		do_exit_divemode_menu		; continue exiting the menu
 
 ;=============================================================================
 
@@ -210,15 +206,15 @@
 
 do_switch_sp:							; entry point when coming from manual setpoint selection (CCR)
 	decf	menu_pos_cur,W				; 1-5 -> 0-4
-	lfsr	FSR1,opt_setpoint_cbar
-	movff	PLUSW1,char_I_const_ppO2	; setup fixed setpoint
+	lfsr	FSR1,opt_setpoint_cbar		; load base address
+	movff	PLUSW1,char_I_const_ppO2	; set selected setpoint
  IFDEF _external_sensor
 	call	transmit_setpoint			; transmit current setpoint from WREG (in cbar) to external electronics
  ENDIF
 	bcf		sp_fallback					; clear fallback condition (stops fallback warning)
 	clrf	WREG						; switch to fixed SP
 	movff	WREG,opt_ccr_mode			; =0: Fixed SP (CCR) / calculated (pSCR), =1: Sensor, =2: Auto SP
-	bra		do_switch_sp_com
+	bra		do_switch_sp_com			; continue with common part
 
 
 do_switch_sp_calc:						; entry point when coming from switch to calculated ppO2 (pSCR)
@@ -226,7 +222,7 @@
 	clrf	WREG						; switch to fixed SP
 	movff	WREG,opt_ccr_mode			; =0: Fixed SP (CCR) / calculated (pSCR), =1: Sensor, =2: Auto SP
 	movff	WREG,char_I_const_ppO2		; set setpoint to 0, this forces deco engine to take the computed ppO2
-	;bra	do_switch_sp_com
+	;bra	do_switch_sp_com			; continue with common part
 
 
 do_switch_sp_com:						; common part
@@ -239,12 +235,12 @@
 	bcf		better_dil_available		; =1: a better diluent is available and a gas change is advised in dive mode
 	bcf		better_gas_blinking			; clear blinking flag
 	bcf		better_dil_blinking			; clear blinking flag
-	call	dive_customview_mask		; redraw custom view mask to (eventually) rewrite "ppO2(Dil)" to "ppO2" or SAC label
+	call	dive_customview_callup		; redraw custom view mask to (if applicable) rewrite "ppO2(Dil)" to "ppO2" or SAC label
 
 	bsf		request_back_to_loop		; indicate that it is a switchback from OC bailout to CCR/pSCR loop
-	bsf		request_gaschange			; initiate reconfiguration to loop mode on last diluent
+	bsf		request_gas_change			; initiate reconfiguration to loop mode on last diluent
 
-	bra		do_exit_divemode_menu		; continue with exiting menu code
+	bra		do_exit_divemode_menu		; continue exiting the menu
 
 
 do_divemode_gaslist_bail:				; entry point from CCR/pSCR to bailout to OC gases
@@ -263,6 +259,7 @@
  ENDIF
 	bsf		short_gas_descriptions		; do not show "Gas x" etc.
 	bsf		better_gas_hint				; mark the gas which is the best gas/diluent
+	bsf		color_code_gases			; color-code the gases/diluents by their ppO2 and current depth
 	movf	best_gas_number,W			; load number of best gas (1-5)into WREG
  IFDEF _ccr_pscr
 	btfsc	is_diluent_menu				; in diluent selection?
@@ -274,23 +271,25 @@
 	movlw	.1							; YES - default to first gas/dil
 do_divemode_gaslist_1:
 	movwf	menu_pos_cur				; position cursor to best gas/dil (or first option if none avail)
+
 	MENU_BEGIN	tGaslist,	.6
 		MENU_DYNAMIC	gaslist_strcat_gas_cd,	do_switch_gas
 		MENU_DYNAMIC	gaslist_strcat_gas_cd,	do_switch_gas
 		MENU_DYNAMIC	gaslist_strcat_gas_cd,	do_switch_gas
 		MENU_DYNAMIC	gaslist_strcat_gas_cd,	do_switch_gas
 		MENU_DYNAMIC	gaslist_strcat_gas_cd,	do_switch_gas
-		MENU_CALL		tMore,					do_divemode_gaslist_more
+		MENU_CALL		tDivemenu_LostGas,		do_lost_gas
 	MENU_END
 
 
-do_divemode_gaslist_more:
-	movlw	.1
-	movwf	menu_pos_cur					; set to first option in dive mode menu
-
-	movff	char_I_O2_ratio,gas6_O2_ratio	; initialize gas6 with currently breathed gas - O2 ratio
+do_gas6_or_exit:
+	btfsc	gas6_or_EXIT					; shall exit?
+	bra		do_exit_divemode_menu			; YES - continue exiting menu
+	movlw	.1								; NO  - select first item
+	movwf	menu_pos_cur					;     - set cursor
+	movff	char_I_O2_ratio,gas6_O2_ratio	;     - initialize gas6 with currently breathed gas - O2 ratio
  IFDEF _helium
-	movff	char_I_He_ratio,gas6_He_ratio	; initialize gas6 with currently breathed gas - He ratio
+	movff	char_I_He_ratio,gas6_He_ratio	;     - initialize gas6 with currently breathed gas - He ratio
  ENDIF
 
 do_divemode_gaslist_more_common:
@@ -301,32 +300,34 @@
 		MENU_CALL		tHePlus,				do_dive_pHe
 		MENU_CALL		tHeMinus,				do_dive_mHe
 		MENU_DYNAMIC	gaslist_strcat_gas6,	do_switch_gas6
-		MENU_CALL		tDivemenu_LostGas,		do_lost_gas
+		MENU_CALL		tExit,					do_exit_divemode_menu
 	MENU_END
  ELSE
 	MENU_BEGIN	tGaslist,	.4
 		MENU_CALL		tO2Plus,				do_dive_pO2
 		MENU_CALL		tO2Minus,				do_dive_mO2
 		MENU_DYNAMIC	gaslist_strcat_gas6,	do_switch_gas6
-		MENU_CALL		tDivemenu_LostGas,		do_lost_gas
 		MENU_CALL		tExit,					do_exit_divemode_menu
 	MENU_END
  ENDIF
 
 
 do_lost_gas:
-	movlw	.1
-	movwf	menu_pos_cur				; set to first option in dive mode menu
+	movlw	.1							; set to first option in dive mode menu
+	movwf	menu_pos_cur				; ...
+	bcf		gas6_or_EXIT				; default to presenting gas6 option
 do_lost_gas_common:
 	bsf		short_gas_descriptions		; do not show "Gas x" etc.
 	bcf		better_gas_hint				; do not mark the best gas/diluent
+	bcf		color_code_gases			; do not color-code the gases/diluents by their ppO2
+
 	MENU_BEGIN	tDivemenu_LostGas, .6
-		MENU_DYNAMIC	gaslist_strcat_gas_cd,	do_toggle_active	; toggle the gas (in)active
-		MENU_DYNAMIC	gaslist_strcat_gas_cd,	do_toggle_active	; toggle the gas (in)active
-		MENU_DYNAMIC	gaslist_strcat_gas_cd,	do_toggle_active	; toggle the gas (in)active
-		MENU_DYNAMIC	gaslist_strcat_gas_cd,	do_toggle_active	; toggle the gas (in)active
-		MENU_DYNAMIC	gaslist_strcat_gas_cd,	do_toggle_active	; toggle the gas (in)active
-		MENU_CALL		tExit,					do_exit_divemode_menu
+		MENU_DYNAMIC	gaslist_strcat_gas_cd,	do_toggle_staged_lost
+		MENU_DYNAMIC	gaslist_strcat_gas_cd,	do_toggle_staged_lost
+		MENU_DYNAMIC	gaslist_strcat_gas_cd,	do_toggle_staged_lost
+		MENU_DYNAMIC	gaslist_strcat_gas_cd,	do_toggle_staged_lost
+		MENU_DYNAMIC	gaslist_strcat_gas_cd,	do_toggle_staged_lost
+		MENU_DYNAMIC	label_do_gas6_or_exit,	do_gas6_or_exit
 	MENU_END
 
 
@@ -338,80 +339,119 @@
 
 
 do_switch_gas:
-	bsf		request_gaschange			; initiate gas change, will also trigger restart of deco_engine
+	bsf		request_gas_change			; initiate gas change, will also trigger restart of deco_engine
+ IFDEF _ccr_pscr
 	btfss	is_bailout_menu				; doing a bailout?
 	bra		do_switch_gas_1				; NO
 	bsf		bailout_mode				; YES - begin bailout mode
+ ENDIF
  IFDEF _cave_mode
-	btfsc	cave_mode					;     - in cave mode?
-	bsf		dive_turned					;       YES - set dive as turned
+	btfsc	cave_mode					;     - cave mode switched on?
+	bsf		request_turn_turn			;       YES - request to turn the dive
+ ENDIF
+ IFDEF _ccr_pscr
+do_switch_gas_1:
+	bcf		sp_fallback					; terminate fallback mode and get rid of its warning if applicable
+	call	dive_customview_callup		; redraw custom view mask to rewrite "ppO2(Dil)" to "ppO2" or SAC label if applicable
  ENDIF
-do_switch_gas_1:
-	bcf		sp_fallback					; eventually terminate fallback mode and get rid of its warning
-	call	dive_customview_mask			; redraw custom view mask to (eventually) rewrite "ppO2(Dil)" to "ppO2" or SAC label
-	;bra	do_exit_divemode_menu		; continue with exiting menu code
+	; revoke staged and lost state on the selected gas
+	lfsr	FSR1,opt_gas_type			; load base address of gas types
+	movff	menu_pos_cur,lo				; copy selected gas to lo
+ IFDEF _ccr_pscr
+	movlw	.5							; load WREG with diluent offset
+	btfsc	is_diluent_menu				; operating on diluents?
+	addwf	lo,F						; YES - add diluent offset to shift 1-5 -> 6-10
+ ENDIF	; _ccr_pscr
+	decf	lo,W						; 1-10 -> 0-4 for gases / 5-9 for diluents with result into WREG
+	bcf		PLUSW1,gas_lost				; revoke lost   state
+ IFDEF _cave_mode
+	bcf		PLUSW1,gas_staged			; revoke staged state
+ ENDIF
+	;bra	do_exit_divemode_menu		; continue exiting the menu
 
 
+; +++ Dive Mode and Cave Mode common exit point +++
 do_exit_divemode_menu:
-	call	timeout_divemode_menu2
-	clrf	STKPTR
-	goto	diveloop_menu_exit
+	call	timeout_divemode_menu2		; check for timeout and do some cleanup
+	clrf	STKPTR						; reset the stack
+	goto	diveloop_menu_exit			; back to the dive loop
 
 
-do_toggle_active:
-	movlw	.5
+do_toggle_staged_lost:
+	movff	menu_pos_cur,lo				; copy selected gas/diluent to lo   (1-5)
+	movf	active_gas,W				; copy currently used gas   to WREG (1-5)
  IFDEF _ccr_pscr
-	btfsc	is_diluent_menu				; operating on diluents?
-	addwf	menu_pos_cur,F				; YES - add offset of 5 to shift 1-5 -> 6-10
+	btfsc	FLAG_oc_mode				; in OC mode?
+	bra		do_toggle_staged_lost_check	; YES - can't be in diluent menu then, check selected gas against gas in use
+	btfsc	bailout_mode				; NO  - in bailout?
+	bra		do_toggle_staged_lost_check	;       YES - can't be in diluent menu then, check selected gas against bailout gas in use
+	btfss	is_diluent_menu				;       NO  - breathing a diluent then, in diluent menu?
+	bra		do_toggle_staged_lost_exec	;             NO  - can modify any gas, no need for a check
+	movf	active_dil,W				;             YES - check selected diluent against diluent in use
  ENDIF
-	decf	menu_pos_cur,W				; 1-10 -> 0-4 for gases / 5-9 for diluents
-	lfsr	FSR1,opt_gas_type			; load base address of gas types
-	movff	PLUSW1,lo					; get gas/dil type
-	tstfsz	lo							; already disabled?
-	bra		do_toggle_active_disable	; NO  - disable   now
-do_toggle_active_enable					; YES - re-enable now
-	lfsr	FSR1,opt_gas_type_backup	; load base address of backed-up gas types
-	movff	PLUSW1,lo					; get backed-up gas/dil type
+do_toggle_staged_lost_check:
+	cpfseq	lo							; selected gas/dil = currently used gas/dil?
+	bra		do_toggle_staged_lost_exec	; NO  - can set selected gas/dil to lost or staged
+	bra		do_lost_gas_common			; YES - gas/dil in use, can not set to lost or staged, back to menu
+do_toggle_staged_lost_exec:
 	lfsr	FSR1,opt_gas_type			; load base address of gas types
-	movff	lo,PLUSW1					; restore gas type
-	bra		do_toggle_active_common
-do_toggle_active_disable:				; disable gas / diluent
-	;lfsr	FSR1,opt_gas_type			; (still set)
-	clrf	PLUSW1						; set type to disabled (0=disabled, 1=first, 2=travel/normal, 3=deco/-)
-do_toggle_active_common:
-	movlw	.5
+	bcf		better_gas_blinking			; clear blinking flag for gases    to avoid "leftovers"
  IFDEF _ccr_pscr
+	bcf		better_dil_blinking			; clear blinking flag for diluents to avoid "leftovers"
+	movlw	.5							; load WREG with diluent offset
 	btfsc	is_diluent_menu				; operating on diluents?
-	subwf	menu_pos_cur,F				; YES - back to 1-5
-	bcf		better_dil_blinking			; clear blinking flag for diluents to avoid "leftovers"
- ENDIF
-	bcf		better_gas_blinking			; clear blinking flag for gases    to avoid "leftovers"
-	call	restart_deco_engine_wo_ceiling ; invalidate deco data (but not the ceiling) and restart deco engine
-	bra		do_lost_gas_common
+	addwf	lo,F						; YES - add diluent offset to shift 1-5 -> 6-10
+ ENDIF	; _ccr_pscr
+ IFDEF _cave_mode
+	TSTOSS	opt_cave_mode				; cave mode switched on?
+	bra		do_toggle_staged_lost_3		; NO  - just toggle lost state
+	decf	lo,W						; YES - 1-10 -> 0-4 for gases / 5-9 for diluents with result into WREG
+	btfsc	PLUSW1,gas_staged			;     - gas currently set as staged?
+	bra		do_toggle_staged_lost_1		;       YES - set as lost now
+	btfsc	PLUSW1,gas_lost				;       NO  - gas currently set as lost?
+	bra		do_toggle_staged_lost_2		;             YES - set as available now
+	;bra	do_toggle_staged_lost_0		;             NO  - set as staged    now
+do_toggle_staged_lost_0:
+	bsf		PLUSW1,gas_staged			; set    staged state
+	bra		do_toggle_staged_lost_4		; continue with restarting deco engine
+do_toggle_staged_lost_1:
+	bcf		PLUSW1,gas_staged			; revoke staged state
+	bsf		PLUSW1,gas_lost				; set    lost   state
+	bra		do_toggle_staged_lost_4		; continue with restarting deco engine
+do_toggle_staged_lost_2:
+	bcf		PLUSW1,gas_lost				; revoke lost   state
+	bra		do_toggle_staged_lost_4		; continue with restarting deco engine
+ ENDIF	; _cave_mode
+do_toggle_staged_lost_3:
+	decf	lo,W						; 1-10 -> 0-4 for gases / 5-9 for diluents with result into WREG
+	btg		PLUSW1,gas_lost				; toggle lost state
+do_toggle_staged_lost_4:
+	bsf		request_gas_update			; request to update the gases
+	bsf		gas6_or_EXIT				; switch 6th menu item from gas6 to exit
+	bra		do_lost_gas_common			; back to the menu
 
 
 do_dive_pO2:
-	incf	gas6_O2_ratio,F				; O2++
+	incf	gas6_O2_ratio,F				; increment O2 %
  IFDEF _helium
-	movf	gas6_He_ratio,W
-	addwf	gas6_O2_ratio,W
+	movf	gas6_He_ratio,W				; get He %
+	addwf	gas6_O2_ratio,W				; add O2 %
  ELSE
-	movf	gas6_O2_ratio,W
+	movf	gas6_O2_ratio,W				; get O2 %
  ENDIF
-	movwf	lo
-	movlw	.101
-	cpfslt	lo							; O2 + He < 101 ?
-	decf	gas6_O2_ratio,F				; O2-- (unchanged)
+	movwf	lo							; copy to lo
+	movlw	.101						; O2 + He < 101 
+	cpfslt	lo							; ... ?
+	decf	gas6_O2_ratio,F				; NO  - decrement O2 again
 	bra		do_divemode_gaslist_more_common
 
 
 do_dive_mO2:
-	decf	gas6_O2_ratio,F				; O2--
-	movlw	gaslist_min_o2
+	decf	gas6_O2_ratio,F				; decrement O2 %
+	movlw	gaslist_min_o2				; get minimum value
 	cpfslt	gas6_O2_ratio				; O2 < minimum allowed %O2 ?
-	bra		do_dive_mO2_done			; NO
-	movlw	gaslist_min_o2				; YES - restore minimum
-	movwf	gas6_O2_ratio
+	bra		do_dive_mO2_done			; NO  - value is valid
+	movwf	gas6_O2_ratio				; YES - set O2 % to minimum
 do_dive_mO2_done:
 	bra		do_divemode_gaslist_more_common
 
@@ -420,17 +460,17 @@
  IFDEF _helium
 
 do_dive_pHe:
-	incf	gas6_He_ratio,F				; He++
-	movf	gas6_He_ratio,W
-	addwf	gas6_O2_ratio,W
-	movwf	lo
-	movlw	.101
-	cpfslt	lo							; O2 + He < 101 ?
-	decf	gas6_He_ratio,F				; YES - He-- (unchanged)
+	incf	gas6_He_ratio,F				; increment He %
+	movf	gas6_He_ratio,W				; get He %
+	addwf	gas6_O2_ratio,W				; add O2 %
+	movwf	lo							; copy to lo
+	movlw	.101						; O2 + He < 101
+	cpfslt	lo							; ... ?
+	decf	gas6_He_ratio,F				; YES - decrement He again
 	bra		do_divemode_gaslist_more_common
 
 do_dive_mHe:
-	decf	gas6_He_ratio,F				; He--
+	decf	gas6_He_ratio,F				; decrement He %
 	bnn		do_dive_mHe_done			; H2 < 0 ?
 	clrf	gas6_He_ratio				; YES - reset to 0
 do_dive_mHe_done:
@@ -485,11 +525,11 @@
 
 
 do_divemode_sensor:
-	movlw	index_ppo2_sensors-1		; custom view number one below ppO2 sensors
-	movwf	active_customview			; set custom view number
-	bsf		request_next_custview		; initiate toggle to desired custom view -> ppO2 sensors
-	movlw	.1
-	movwf	menu_pos_cur				; set to 1st option: use sensors
+	movlw	index_ppo2_sensors			; number of ppO2 sensors custom view
+	movwf	active_customview			; set     the custom view number
+	call	dive_customview_callup		; call-up the custom view
+	movlw	.1							; set to 1st option: use sensors
+	movwf	menu_pos_cur				; ...
 
 do_return_divemode_sensor:
 	MENU_BEGIN	tGaslist,	.6
@@ -501,10 +541,10 @@
 		MENU_CALL		tDiveHudMask3,			do_toggle_sensor
 	MENU_END
 
-
 do_divemode_setpoint_pscr:
 	movlw	.1
 	movwf	menu_pos_cur				; set to 1st option: use calculated ppO2
+
 	MENU_BEGIN	tGaslist,	.6
 		MENU_CALL		tCalculated,			do_switch_sp_calc
 		MENU_CALL		tDivemenu_UseSensor,	do_switch_sensor
@@ -514,6 +554,10 @@
 		MENU_CALL		tDiveHudMask3,			do_toggle_sensor
 	MENU_END
 
+do_switch_sensor:						; entry point when coming from switch to sensor
+	movlw	.1							; switch to sensor
+	movff	WREG,opt_ccr_mode			; =0: fixed SP (CCR) / calculated (pSCR), =1: Sensor, =2: Auto SP
+	bra		do_switch_sp_com			; continue with common part
 
 do_toggle_sensor:
 	movff	menu_pos_cur,lo				; backup position
@@ -521,11 +565,11 @@
 	decf	menu_pos_cur,f				; 3, 4, 5 ->  2, 3, 4
 	decf	menu_pos_cur,f				; 2, 3, 4 ->  1, 2, 3
 	dcfsnz	menu_pos_cur				; 1, 2, 3 ->  0, 1, 2
-	btg		use_O2_sensor1				;			  = 
+	btg		use_O2_sensor1				;             = 
 	dcfsnz	menu_pos_cur				; 0, 1, 2 -> -1, 0, 1
-	btg		use_O2_sensor2				;				 =
+	btg		use_O2_sensor2				;                =
 	dcfsnz	menu_pos_cur				; -1,0, 1 -> -2,-1, 0
-	btg		use_O2_sensor3				;					=
+	btg		use_O2_sensor3				;                   =
 	movff	lo,menu_pos_cur				; restore position
 	bra		do_return_divemode_sensor
 
@@ -533,5 +577,70 @@
  ENDIF	; _ccr_pscr
 
 ;=============================================================================
+;
+; Cave Mode Menu
+;
+
+ IFDEF _cave_mode
+
+do_return_main_cavemenu:
+	call	menu_processor_pop					; drop selection from menu stack
+	incf	selected_item,W						; item numbers start with 0, menu positions with 1
+	movwf	menu_pos_cur						; position cursor where we came from
+	bra		do_main_cavemenu_common				; continue with common part
+
+	global	do_main_cavemenu
+do_main_cavemenu:
+	bsf		custom_view_locked					; lock custom view
+	movff	active_customview,backup_customview	; back up current custom view
+	call	menu_processor_reset				; restart from first icon
+	movlw	.1									; set cursor to first menu item by default
+	btfsc	dive_turned							; dive turned ?
+	movlw	.4									; YES - set cursor on waypoint out item
+	btfss	cave_mode							; cave mode switched off ?
+	movlw	.3									; YES - set cursor on cave mode off/on menu item
+	movwf	menu_pos_cur						; actually set cursor position
+
+	; The helper functions for MENU_DYNAMIC can be found in
+	; gaslist.asm as it does not work to include them here.
+
+do_main_cavemenu_common:
+	movlw	index_cave_waypoints				; get  number of cave waypoints custom view
+	movwf	active_customview					; set  custom view number
+	call	dive_customview_callup				; draw custom view
+
+	MENU_BEGIN	tMainMenu,	.6
+		MENU_DYNAMIC	label_do_wp_set,		do_waypoint_set			; 1
+		MENU_DYNAMIC	label_do_turn_dive,		do_turndive_toggle		; 2
+		MENU_CALL		tDivemenu_off_on,		do_cavemode_toggle		; 3
+		MENU_DYNAMIC	label_do_wp_out,		do_waypoint_out			; 4
+		MENU_DYNAMIC	label_do_wp_in,			do_waypoint_in			; 5
+		MENU_CALL		tExit,					do_exit_divemode_menu	; 6
+	MENU_END
+
+
+do_waypoint_set:
+	bsf		request_waypoint_set		; set request flag
+	bra		do_return_main_cavemenu		; back to menu
+
+do_turndive_toggle:
+	bsf		request_turn_toggle			; set request flag
+	bra		do_return_main_cavemenu		; back to menu
+
+do_cavemode_toggle:
+	bsf		request_cave_toggle			; set request flag
+	bra		do_return_main_cavemenu		; back to menu
+
+do_waypoint_out:
+	bsf		request_waypoint_out		; set request flag
+	bra		do_return_main_cavemenu		; back to menu
+
+do_waypoint_in:
+	bsf		request_waypoint_in			; set request flag
+	bra		do_return_main_cavemenu		; back to menu
+
+ ENDIF	; _cave_mode
+
+;=============================================================================
 
 	END