fixes and changes from code review

diff --git a/detpic/panic.asm b/detpic/panic.asm
index 9f306858d996e34e6035be60a37f1072b562b5c2..29bf2c9bab098add37775d28f85abaa914c00d6c 100644 (file)
--- a/detpic/panic.asm
+++ b/detpic/panic.asm
@@ -12,15 +12,16 @@
 
        udata_acs
 
+; used in panic routine for temporary storage:
+
 flash_pattern          res     1
 morse_counter          res     1
 register_counter       res     1
 bit_counter            res     1
 
-; used in panic macro for temporary storage
-panic_address  res     1       ; stores condensed form of message start addr.
-panic_morse    res     1       ; stores # bytes of morse msg in panic readout
-panic_regs     res     1       ; stores # registers in panic readout
+panic_address  res     1       ; condensed form of message start addr.
+panic_morse    res     1       ; # bytes of morse msg in panic readout
+panic_regs     res     1       ; # registers in panic readout
 
 
 ;****************************************************************************
@@ -29,10 +30,6 @@ panic_regs   res     1       ; stores # registers in panic readout
 
 ;****************************************************************************
 
-; first, copy the panic message address out of WREG  
-
-        mov_wf   panic_address
-
 panic_routine
 ; switch off interrupts and power
 ; reconfigure timer0 for writing diagnostic msg to the LED
@@ -40,6 +37,12 @@ panic_routine
         clr_f    INTCON        ; disable all interrupts EVER
         bc_f     PORTC,1       ; switch off booster
 
+; now we have time to copy the panic message address out of WREG
+; (turning off interrupts is urgent (we might get interrupted while
+;  panicing which would be bad because we might forget to panic).
+
+        mov_wf   panic_address
+
 
 ; re-initialise timer0 config
         bc_f     T0CON,6       ; p107 Timer0 -> 16bit mode
@@ -53,7 +56,7 @@ panic_routine
 ; back from condensed message start addr. stored in panic_address
 
 panic_loop
-       mov_lw  4
+       mov_lw  4 ; size of each message's details
        mul_wf  panic_address
        mov_ff  PRODL,TBLPTRL           
        mov_ff  PRODH,WREG
@@ -78,7 +81,7 @@ panic_loop
        call    waiting
        call    waiting
        call    waiting
-       call    morsemsg        ; transmit SOS in red
+       call    morsemsg        ; transmit morse in red
        call    led_black
        call    waiting
        call    waiting
@@ -92,8 +95,7 @@ panic_loop
 ; PANIC SUBROUTINES
 
 morsemsg
-; wrapper round readout to flash the per-pic led red for a
-; (currently 4-byte) morse msg
+; wrapper round morse_readout to flash the per-pic led red for a morse msg
 
 morse_msg_start
        clr_f           morse_counter           ; clear loop counter
@@ -113,7 +115,7 @@ morse_loop
 ;--------------------------
 morse_readout
 
-; Flashes the per-pic led red(0) in a specified pattern.
+; Flashes the per-pic led and black in a specified pattern.
 ;
 ; The pattern is specified as the state for 8 identically-long time
 ; periods each as long as a morse `dot', encoded into a byte with
@@ -123,13 +125,14 @@ morse_readout
 ; flash_pattern                flash pattern           preserved
 ; bit_counter          any                     undefined
 
-       clr_f           bit_counter             ; clear loop counter
+       mov_lw          8
+       mov_wf          bit_counter
        rr_f            flash_pattern
 
 morse_readout_loop
-       mov_fw          panic_regs
-       cmp_fw_ifge     bit_counter             ; if loop counter >=panic_regs, return
+       dec_f_ifz       bit_counter             ; done all the bits yet ?
        return
+       ; No:
 
        rl_f            flash_pattern           ; top bit goes into N, 
                                                ;ie Negative if 1
@@ -143,8 +146,6 @@ morse_readout_if_led_1
        call            led_red
 
 morse_readout_endif_led
-       inc_f           bit_counter             ; increment loop counter
-       call            waiting
        bra             morse_readout_loop
 
 ;--------------------------
@@ -201,21 +202,21 @@ register_readout
 
 
 register_readout_loop
-        movlw          8
+        mov_lw         8
         cmp_fw_ifge    bit_counter             ; if loop counter >=8 (register 
                                                ; length), return
         return
 
-        movlw          4
+        mov_lw         4
         cmp_fw_ifne    bit_counter     ; if loop counter !=4 (nybble length), 
                                        ; skip insertion of extra black space
        goto            not_nybble_boundary
        call            waiting
 
 not_nybble_boundary
-        rlncf          flash_pattern,1         ; top bit goes into N flag, 
+        rl_f           flash_pattern           ; top bit goes into N flag, 
                                                ; ie Negative if 1
-        bn             register_readout_if_led_1
+        bra_n          register_readout_if_led_1
 
 register_readout_if_led_0
         call           led_red
@@ -243,9 +244,9 @@ waiting
         clr_f          TMR0H           ; p107 set high byte of timer0 to 0 (buffered,
                                 ; only actually set when write to tmr0l occurs)
         clr_f          TMR0L           ; set timer0 low byte - timer now set to 0000h
-loop
+waiting_loop
         bt_f_if0 INTCON,TMR0IF         
-        bra     loop           ; wait for timer0 interrupt
+        bra     waiting_loop   ; wait for timer0 interrupt
         return