From: ian <ian>
Date: Fri, 2 Dec 2005 02:48:24 +0000 (+0000)
Subject: points more wip
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ijackson/git?a=commitdiff_plain;h=14616c573ccc11a1a9adc298dfa5bef0047205a1;p=trains.git

points more wip
---

diff --git a/detpic/points.asm b/detpic/points.asm
index 20d72a6..f58745c 100644
--- a/detpic/points.asm
+++ b/detpic/points.asm
@@ -1,37 +1,116 @@
 ;======================================================================
 ; POINTS
+;
+; Expected layout of data at data_points in flash:
+;	4 bytes for each point number
+;		byte 0
+;			pic number for this point
+;			ff indicates unassigned point number
+;		byte 1
+;			index number for this point on relevant pic
+;		byte 2
+;			address of relevant LAT*
+;		byte 3
+;			bit in LAT (eg 0x40 for bit 6)
+;		bytes 1-3 are not defined if number is not assigned
+; address of data_points is guaranteed to be multiple of 256
 
  udata_acs
-point res 1
 
- code
-
-obj_set_up_start macro
-	clr_f	TBLPTRU
-	clr_f	TBLPTRL
-	endm
+ udata 0x300
+our_point_table_ctln2	equ	6
+our_point_table_count	equ	(1 << our_point_table_ctln2)
+our_point_table		res	our_point_table_count * 2
+;	2 bytes for each point, indexed by index number on this pic
+;		1st byte:	LAT* address, or 0 for unassigned
+;		2nd byte:	bit in LAT
 
-obj_select macro
-;	W	object number		-
-	mov_wf	TBLPTRL
-	endm
-	
-obj_setfsr0 macro obj_pic_data, obj_port_data, obj_bit_data, PORTRISLATA
-	mov_lw	pt_pic_data >> 8
-	mov_wf	TBLPTRH
-	
+ code
 
 ;----------------------------------------------------------------------
 points_init
 ; Clears TRIS* bits for all points and sets the
 ; pin to `not triggering'
 
-	mov_lw	pt_num_max
-	mov_wf	point
+	mov_lfsr our_point_table, 0	; FSR0 points to point lookup table
+	mov_lw	our_point_table_count * 2
 
-	obj_set_up_start
+points_init_clear_loop
+	clr_f	POSTINC1
+	dec_w_ifnz
+	bra	points_init_clear_loop
+	; otherwise, done:
+
+					; During this loop:
+	clr_wf	TBLPTRU
+	mov_lw	(data_points >> 8)
+	mov_wf	TBLPTRH
+	clr_f	TBLPTRL			; TBLPTR* -> to point data
+
+	set_f	FSR1H			; FSR1 -> LAT*, TRIS*
+
+	mov_lfsr our_point_table, 0	; FSR0 -> point lookup table
 
 points_init_loop
+	mov_lw	(data_points_end >> 8)
+	cmp_fw_ifge TBLPTRH
+	bra	points_init_loop_exit
+
+	tblrd	*+
+	dw	0xffff			; TABLAT = pic number
+
+	mov_fw	picno
+	cmp_fw_ifne TABLAT
+	bra	points_init_loop_ifnot_ours
+
+	tblrd	*+
+	dw	0xffff			; TABLAT = index number
+
+	mov_lw	0xff << our_point_table_ctln2
+	and_wfw	TABLAT
+	bra_nz	bad_pointtable_index
+
+	rl_fw	TABLAT
+	mov_wf	FSR0L			; FSR0 -> our table entry
+
+	tst_f_ifnz INDF0
+	bra_nz	bad_pointtable_clash
+
+	tblrd	*+
+	dw	0xffff			; TABLAT = LAT* address
+
+	mov_fw	TABLAT
+	mov_wf	POSTINC0		; store LAT* address; FSR0 -> bit
+	mov_wf	FSR1L			; FSR1 -> LAT*
+	
+	tblrd	*+
+	dw	0xffff			; TABLAT = bit value
+
+	mov_fw	TABLAT
+	mov_wf	INDF0			; store bit value
+
+	com_w				; W = ~bit
+	and_wff	INDF1			; clear the LAT* bit (point inactive)
+	pin_vh	pall_pt0reverse ; except pt0 which is backwards
+
+	mov_lw	TRISA-LATA
+	add_wf	FSR1L			; FSR1 -> TRIS*
+	com_fw	TABLAT			; W = ~bit
+	and_wff	INDF1			; make the pin an output
+
+	bra	points_init_loop
+
+points_init_loop_ifnot_ours
+	tblrd	*+
+	tblrd	*+
+	tblrd	*+
+	bra	points_init_loop
+
+
+	
+
+	clr_f	INDF1
+
 	
 
 ;----------------------------------------------------------------------