; but this may be something to try in debugging if stuff doesn't work
-advance_write_buffer
- debug 'i' ; write 'i' to serial port
-; check if on 1st byte of new buffer anyway (i.e. last 4 bits = 0)
- movf FROMSERIAL,0,0 ; copy FROMSERIAL pointer location to W
- andlw 0xF ; investigate last 4 bits
+advance_write_buffer
-; if zero (i.e. overflowed to next buffer), branch to overflow check
- bz fromserial_overflow
-
-; if not zero, clear low 4 bits of FROMSERIAL and increment top 4 bits
+; clear low 4 bits of FROMSERIAL and increment top 4 bits
; aaaabbbb -> bbbbaaaa -> bbbb(aaaa+1) -> 0000(aaaa+1) -> (aaaa+1)0000
debug '5' ; write 'h' to serial port
swapf FROMSERIAL,1,0
andwf FROMSERIAL,1,0
swapf FROMSERIAL,1,0
-fromserial_overflow
; clear bit 6 (will set back to buffer 0 if has overflowed to 4)
debug '6' ; write 'h' to serial port
bcf FROMSERIAL,6,0
advance_pointer
debug 't' ; write 't' to serial port
+
; currently on bit 7 of the byte, after having read rest of byte to
; track; check whether it is 1 or 0
-
movff TOTRACK,FSR1L
movlw 5
movwf FSR1H,0
+
+; if set, move to next buffer
btfsc INDF1,7,0
- bra advance_read_buffer
- bra advance_read_byte
+ debug 'F'
+ btfsc INDF1,7,0
+ call advance_read_buffer
+; if not set, move to next byte of samebuffer (increment TOTRACK)
+; (will be on bit 7 at this point anyway so no need to change TOTRACKBIT)
+ btfss INDF1,7,0
+ debug 'Y'
+ btfss INDF1,7,0
+ incf TOTRACK,1,0
+ return
advance_read_buffer
- debug 'u' ; write 'u' to serial port
-;*** I suggest swapping this and advance_read_byte round, since
-;*** advance_read_byte is a more `inner' bit of the `loop' -iwj
; move pointer to next buffer
-
-; check if on 1st byte of new buffer anyway (i.e. last 4 bits = 0)
- movff TOTRACK,WREG ; copy TOTRACK pointer location to W
- andlw 0xF ; investigate last 4 bits
-
-
-; GIONG WRONG HERE - should be klnoopqstu7895, missing out 78 = advance to next buffer
-; MUST advance byte before trying to advance buffer
-#
-
-; if zero (i.e. overflowed to next buffer), branch to overflow check
- bz totrack_overflow
-
-; if not zero, clear low 4 bits of TOTRACK and increment top 4 bits
+; clear low 4 bits of TOTRACK and increment top 4 bits
; aaaabbbb -> bbbbaaaa -> bbbb(aaaa+1) -> 0000(aaaa+1) -> (aaaa+1)0000
debug '7' ; write 'v' to serial port
swapf TOTRACK,1,0
swapf TOTRACK,1,0
debug '8' ; write 'v' to serial port
-totrack_overflow
; clear bit 6 (will set back to buffer 0 if has overflowed to 4)
bcf TOTRACK,6,0
debug '9' ; write 'v' to serial port
- retfie 1
-
-; write na=cb=1 and return
-
-; bra one_bit_to_track
-;*** oh, we always introduce a one bit in between ? *confused* -iwj
-
-
-
-advance_read_byte
- debug 'v' ; write 'v' to serial port
-; advance to next byte of buffer (increment TOTRACK)
-; (will be on bit 7 at this point anyway so no need to change TOTRACKBIT)
-
- incf TOTRACK,1,0
- debug '6' ; write 'v' to serial port
- retfie 1
-
-
-; set na=cb=new bit value
-
-; movff TOTRACK,FSR1L ; set low byte of IND1 pointer
-; movlw 5
-; movwf FSR1H,0 ; set high byte of IND1 pointer
-; movff INDF1,WREG
-; andwf TOTRACKBIT,0,0 ; mask out bit to be transmitted
-;*** This is the same code as the 2nd stanza in read_from_buffer,
-;*** above. Surely it should be made common (eg a subroutine) ? -iwj
-
-; bz zero_bit_to_track
-; bra one_bit_to_track
-;*** zero_bit_to_track and one_bit_to_track end up calling advance_bit -
-;*** is that right ? *confused* -iwj
-
+ return
; but this may be something to try in debugging if stuff doesn't work
-advance_write_buffer
- debug 'i' ; write 'i' to serial port
-; check if on 1st byte of new buffer anyway (i.e. last 4 bits = 0)
- movf FROMSERIAL,0,0 ; copy FROMSERIAL pointer location to W
- andlw 0xF ; investigate last 4 bits
+advance_write_buffer
-; if zero (i.e. overflowed to next buffer), branch to overflow check
- bz fromserial_overflow
-
-; if not zero, clear low 4 bits of FROMSERIAL and increment top 4 bits
+; clear low 4 bits of FROMSERIAL and increment top 4 bits
; aaaabbbb -> bbbbaaaa -> bbbb(aaaa+1) -> 0000(aaaa+1) -> (aaaa+1)0000
debug '5' ; write 'h' to serial port
swapf FROMSERIAL,1,0
andwf FROMSERIAL,1,0
swapf FROMSERIAL,1,0
-fromserial_overflow
; clear bit 6 (will set back to buffer 0 if has overflowed to 4)
debug '6' ; write 'h' to serial port
bcf FROMSERIAL,6,0
advance_pointer
debug 't' ; write 't' to serial port
+
; currently on bit 7 of the byte, after having read rest of byte to
; track; check whether it is 1 or 0
-
movff TOTRACK,FSR1L
movlw 5
movwf FSR1H,0
+
+; if set, move to next buffer
btfsc INDF1,7,0
- bra advance_read_buffer
- bra advance_read_byte
+ debug 'F'
+ btfsc INDF1,7,0
+ call advance_read_buffer
+; if not set, move to next byte of samebuffer (increment TOTRACK)
+; (will be on bit 7 at this point anyway so no need to change TOTRACKBIT)
+ btfss INDF1,7,0
+ debug 'Y'
+ btfss INDF1,7,0
+ incf TOTRACK,1,0
+ return
advance_read_buffer
- debug 'u' ; write 'u' to serial port
-;*** I suggest swapping this and advance_read_byte round, since
-;*** advance_read_byte is a more `inner' bit of the `loop' -iwj
; move pointer to next buffer
-
-; check if on 1st byte of new buffer anyway (i.e. last 4 bits = 0)
- movff TOTRACK,WREG ; copy TOTRACK pointer location to W
- andlw 0xF ; investigate last 4 bits
-
-
-; GIONG WRONG HERE - should be klnoopqstu7895, missing out 78 = advance to next buffer
-; MUST advance byte before trying to advance buffer
-#
-
-; if zero (i.e. overflowed to next buffer), branch to overflow check
- bz totrack_overflow
-
-; if not zero, clear low 4 bits of TOTRACK and increment top 4 bits
+; clear low 4 bits of TOTRACK and increment top 4 bits
; aaaabbbb -> bbbbaaaa -> bbbb(aaaa+1) -> 0000(aaaa+1) -> (aaaa+1)0000
debug '7' ; write 'v' to serial port
swapf TOTRACK,1,0
swapf TOTRACK,1,0
debug '8' ; write 'v' to serial port
-totrack_overflow
; clear bit 6 (will set back to buffer 0 if has overflowed to 4)
bcf TOTRACK,6,0
debug '9' ; write 'v' to serial port
- retfie 1
-
-; write na=cb=1 and return
-
-; bra one_bit_to_track
-;*** oh, we always introduce a one bit in between ? *confused* -iwj
-
-
-
-advance_read_byte
- debug 'v' ; write 'v' to serial port
-; advance to next byte of buffer (increment TOTRACK)
-; (will be on bit 7 at this point anyway so no need to change TOTRACKBIT)
-
- incf TOTRACK,1,0
- debug '6' ; write 'v' to serial port
- retfie 1
-
-
-; set na=cb=new bit value
-
-; movff TOTRACK,FSR1L ; set low byte of IND1 pointer
-; movlw 5
-; movwf FSR1H,0 ; set high byte of IND1 pointer
-; movff INDF1,WREG
-; andwf TOTRACKBIT,0,0 ; mask out bit to be transmitted
-;*** This is the same code as the 2nd stanza in read_from_buffer,
-;*** above. Surely it should be made common (eg a subroutine) ? -iwj
-
-; bz zero_bit_to_track
-; bra one_bit_to_track
-;*** zero_bit_to_track and one_bit_to_track end up calling advance_bit -
-;*** is that right ? *confused* -iwj
-
+ return
~ijackson / trains.git / commitdiff