P2 Tricks, Traps & Differences between P1 (general discussion)

1234568»

Comments

  • @Evan,
    Basically they are the same. My table tries to show how the ROM code works in sequence down the page. The net results are the same.
  • Well, you've definitely got errors:
    - The first line "Reset...": The pull-up on P59 locks in Serial boot only. It prevents any attempt to boot from Flash or SD.
    - The second line "try FLASH...": Says it'll fall back to SD. But there isn't any combinations in which Flash falls back to SD, or SD falls back to Flash.
  • AJLAJL Posts: 332
    edited 2019-11-20 - 20:46:07
    So here's my assessment of Cluso's table of what the code does compared to what the Google doc claims (and may have been the intent)
    P59	P60	P61		Actions	                 Same as Google Doc
    None	None	None		Serial, Stop	         Yes
    None	None	Up		Flash, Serial, Stop 	 No, missing first Serial 100ms block
    None	Up	None		SD, Serial, Stop	 Yes
    None	Up	Up		Flash, SD, Serial, Stop	 Absent
    Up	None	None		Serial, Stop	         Yes
    Up	None	Up		Serial, Flash, Stop	 No, claims Flash ignored
    Up	Up	None		Serial, SD, Stop	 No, claims SD ignored
    Up	Up	Up		Serial, Flash, SD, Stop	 No, claims Flash and SD ignored
    Down	None	None		Stop	                 No
    Down	None	Up		Flash, Stop    	         Yes
    Down	Up	None		SD, Stop	         Yes
    Down	Up	Up		Flash, SD, Stop	         Absent
    

    Postedit: Fixed language above.
  • Cluso99Cluso99 Posts: 16,374
    edited 2019-11-20 - 08:21:01
    Here are extracts from the ROM Boot Code... (cannot get any more definitive than that which is what I used)
    Postedit - except I read it wrong :(
    .....
                       ' If pull-up on spi_di then try serial
                       '
    fc06c 01b fb4c76ed 		callpa	#spi_di,#check_pullup
    fc070 01c cd9007cc 	if_c	jmp	#reset_serial
                       '
                       '
                       ' If pull-up on spi_cs then try to load from SPI memory
                       '
    fc074 01d fb4c7aeb 		callpa	#spi_cs,#check_pullup
    fc078 01e cd90000c 	if_c	jmp	#try_spi
                       '
                       '
                       ' If pull-up on spi_ck (also sd_cs) then try to load from SD card
                       '
    fc07c 01f fb4c78e9 		callpa	#spi_ck,#check_pullup
    fc080 020 cd8fc560 	if_c	jmp	#@_start_sdcard
                       '
                       '
                       ' If no pull-down on spi_di then try serial
                       '
    fc084 021 fd900378 		jmp	#try_serial
                       '
                       '
                       ' Try to load from SPI memory
                       '
    fc088 022 fd647a59 try_spi		drvh	#spi_cs			'drive spi_cs high
    fc08c 023 fd647858 		drvl	#spi_ck			'drive spi_ck low
    .....
    fc100 040          .sum
    fc100 040 f20acb52 		cmp	y,csum		wz	'verify checksum, z=1 if okay
    fc104 041 f4868e00 		bitz	flags,#spi_ok		'if program verified, set spi_ok flag
    fc108 042          .fail
                       '
                       '
                       ' If SPI failed, check for pull-up on spi_ck (also sd_cs)
                       '
    fc108 042 5b4c78c6   if_nz		callpa	#spi_ck,#check_pullup	'if no SPI program, check for pull-up on spi_ck (also sd_cs)
    fc10c 043 4d8fc560   if_nz_and_c	jmp	#@_start_sdcard		'if no SPI program and pull-up on spi_ck, try to load from SD card
                       
    fc110 044 fd9002ec 		jmp	#try_serial		'try serial
    .....
                       ' Try serial if no pull-down on spi_di
                       ' else, run SPI program if valid or float SPI pins and shut down
                       '
    fc12c 100 f40e8e00 try_serial	testb	flags,#spi_ok	wz	'SPI program?
                       
    fc130 101 5d647a50 	if_nz	fltl	#spi_cs			'if no SPI program, float SPI pins
    fc134 102 5d647850 	if_nz	fltl	#spi_ck
                       
    fc138 103 ad65fe28 	if_z	setq	#$FF			'if SPI program, move it into cog $000..$0FF
    fc13c 104 ab040000 	if_z	rdlong	0,#0
                       
    fc140 105 fd647659 		drvh	#spi_di			'check pull-down on spi_di, leave floating
    fc144 106 fb4c7603 		callpa	#spi_di,#check_pulldn	'c=0 if pull-down
                       
    fc148 107 3d900664 	if_nc	jmp	#serial_done		'if pull-down on spi_di, boot if SPI okay (z=1) or shut down
                       
    fc14c 108 fd90041c 		jmp	#reset_serial		'else try serial
                       '
                       '
                       ' Check pin pull-up
                       '
    fc150 109 fd63ec58 check_pullup	drvl	pa			'drive pin low
    fc154 10a fd643c1f check_pulldn	waitx	#30*1			'wait >1us
    fc158 10b fd63ec50 		fltl	pa			'float pin
    fc15c 10c fd652c1f 		waitx	#30*5			'wait >5us
    fc160 10d 0d73ec40 	_ret_	testp	pa		wc	'sample pin
    .....
                       ' Reset serial autobaud/receiver interrupt
                       '
    fc2b8 210 f527f403 reset_serial	andn	dira,#%11		'disable timing measurements for autobaud
                       
    fc2bc 211 fd640025 		setint1	#0			'disable int1
    .....
                       ' Attempt to get serial command
                       '
    fc2f8 220 fd62c81a get_command	getct	x			'reset serial timeout in case SPI program ready
    fc2fc 221 fa62c941 		addct1	x,timeout_per
                       
    fc300 222 f606cc00 		mov	z,#0			'reset string buffer
                       
    fc304 223 fdb001d4 .byte		call	#get_rx			'get byte
                       
    fc308 224 f20ec81b 		cmp	x,#$1B		wz	'esc?
    fc30c 225 ad8fd028 	if_z	jmp	#@_start_taqoz
                       
    fc310 226 f20ec804 		cmp	x,#$04		wz	'ctrl-d?
    fc314 227 ad8fca88 	if_z	jmp	#@_start_monitor
                       
    fc318 228 f91acb66 		rolbyte	y,z,#3			'scroll byte into 2-long/8-byte string buffer
    fc31c 229 f902cd64 		rolbyte	z,x,#0
                       
    fc320 22a f20acb48 		cmp	y,text_prop	wz	'"Prop"?
    fc324 22b 5d9fffdc 	if_nz	jmp	#.byte
                       
    fc328 22c f20acd4c 		cmp	z,text_txt	wz	'"_Txt"?
    fc32c 22d ad90005c 	if_z	jmp	#command_txt
                       
    fc330 22e f20acd4b 		cmp	z,text_hex	wz	'"_Hex"?
    fc334 22f ad9000b0 	if_z	jmp	#command_hex
                       
    fc338 230 f20acd4a 		cmp	z,text_clk	wz	'"_Clk"?
    fc33c 231 ad900018 	if_z	jmp	#command_clk
                       
    fc340 232 f20acd49 		cmp	z,text_chk	wz	'"_Chk"?
    fc344 233 5d9fffbc 	if_nz	jmp	#.byte
    .....
                       ' Serial done
                       ' on entry, z=1 if SPI program
                       '
    fc4fc 2a1 fdb00044 serial_done	call	#reset_pins		'reset pins
                       
    fc500 2a2 ad9ff574 	if_z	jmp	#0			'if SPI program, run it, else shut down
                       
    fc504 2a3 fd62c801 shut_down	cogid	x			'get cogid (in case jumped to from outside)
    fc508 2a4 fd640200 		hubset	#1			'set 20KHz oscillator
    fc50c 2a5 fd62c803 		cogstop	x			'shut down cog (floats pins)
    .....
    fc560     f6079a00 _Start_SDcard   mov     skiprun,          #0            ' load/run MBR/VOL code                         \ --tweek2--
    fc564     fdb00050                 call    #@_SDcard_Init0                 ' Init/CSD/CID/MBR/VOL/FSI/FAT (skiprun=0)      | --tweek2--
    fc568     adb00290         if_e    call    #@_readDIR                      ' read directory for filenames
                       ''              mov     skiprun,          #0            ' load/run <file>              (already 0)
    fc56c     adb00378         if_e    call    #@_readFILE                     ' read/load/run the file
    fc570     fdb004ec                 call    #@_releaseDO                    ' /CS=1, send CLKs, tristate CS/CK/DI/DO        | --tweek2--
    fc574     fd800100                 JMP     #try_serial                     ' failed: so go back and try serial
    
  • Cluso99Cluso99 Posts: 16,374
    edited 2019-11-20 - 08:26:38
    evanh wrote: »
    Well, you've definitely got errors:
    - The first line "Reset...": The pull-up on P59 locks in Serial boot only. It prevents any attempt to boot from Flash or SD.
    - The second line "try FLASH...": Says it'll fall back to SD. But there isn't any combinations in which Flash falls back to SD, or SD falls back to Flash.
    ok, I think I see an error (need time to check)..
    - The first line "Reset..." says: If a pull-up on P59 it will try Serial (ie it waits some time) and if not valid (ie else) it will move to the next line and try FLASH. STOP.
    - The second line "try FLASH..." says: If a pull-up on P61 it will try FLASH and if not valid (ie else) it will move to the next line and try SD. The code will try SD at code $fc108-fc110.
    - The third line "try SD" says: If a pull-up on P60 it will try SD and if not valid (ie else) it will move to the next line and try Serial. My SD code will return to try serial.
    - The fourth line "try Serial" says: If a pull-down on P59 it will STOP (ie it will not boot from Serial) else it will try SERIAL (which may be again).

  • AJL wrote: »
    So here's my assessment of what the code does compared to what the Google doc claims (and may have been the intent)
    P59	P60	P61		Actions	                 Same as Google Doc
    None	None	None		Serial, Stop	         Yes
    None	None	Up		Flash, Serial, Stop 	 No, missing first Serial 100ms block
    None	Up	None		SD, Serial, Stop	 Yes
    None	Up	Up		Flash, SD, Serial, Stop	 Absent
    Up	None	None		Serial, Stop	         Yes
    Up	None	Up		Serial, Flash, Stop	 No, claims Flash ignored
    Up	Up	None		Serial, SD, Stop	 No, claims SD ignored
    Up	Up	Up		Serial, Flash, SD, Stop	 No, claims Flash and SD ignored
    Down	None	None		Stop	                 No
    Down	None	Up		Flash, Stop    	         Yes
    Down	Up	None		SD, Stop	         Yes
    Down	Up	Up		Flash, SD, Stop	         Absent
    
    Wow, that's massive. Even if it has a few errors that's still way more than either the others.
    None	None	Up		Flash, Serial, Stop 	 No, missing first Serial 100ms block
    
    I can assure you the 100 ms does exist. I worked with Eric to iron out getting loadp2 to make use of it.

  • evanhevanh Posts: 9,693
    edited 2019-11-20 - 09:53:14
    The 100 ms only triggers if a valid SPI boot is detected - uses a checksum at end of first 1 kByte I think. If not valid, it'll drop straight to serial after reading that first 1 kByte of the SPI device.
  • evanhevanh Posts: 9,693
    edited 2019-11-20 - 11:24:44
    Up	None	Up		Serial, Flash, Stop	 No, claims Flash ignored
    
    Reading the source code, I can't see that sequence coming true either. The P59 pull-up means the SPI device is never checked. The test for P59 is first and serial is jumped to immediately. So the spi_ok flag won't get set, therefore the serial timeout will stop the cog.

    EDIT: Same goes for the other two extra cases of P59 pull-up
    Up	Up	None		Serial, SD, Stop	 No, claims SD ignored
    Up	Up	Up		Serial, Flash, SD, Stop	 No, claims Flash and SD ignored
    
    P59 pull-up check is first and the serial code doesn't recheck any pull-up/down states, so will always simply stop after the 60 second timeout.

    EDIT2: Removed a duplicate line.
  • evanh wrote: »
    Up	None	Up		Serial, Flash, Stop	 No, claims Flash ignored
    
    Reading the source code, I can't see that sequence coming true either. The P59 pull-up means the SPI device is never checked. The test for P59 is first and serial is jumped to immediately. So the spi_ok flag won't get set, therefore the serial timeout will stop the cog.

    EDIT: Same goes for the other two extra cases of P59 pull-up
    Up	Up	None		Serial, SD, Stop	 No, claims SD ignored
    Up	Up	Up		Serial, Flash, SD, Stop	 No, claims Flash and SD ignored
    
    P59 pull-up check is first and the serial code doesn't recheck any pull-up/down states, so will always simply stop after the 60 second timeout.

    EDIT2: Removed a duplicate line.

    Yes, I hadn't read the source but was going by Cluso's analysis of the code. I've updated the language in my post to make that clearer.

    Sorry, for adding to the confusion.
  • Oh, I thought you'd previously done your own testing and that's what you'd found. I can't make sense of what Cluso has written.

    I've found Chip's documentation to be pretty bullet proof in general. Many times I've thought I found something wrong only to find I hadn't tested the cases correctly or I've just not understood. The smartpins were a good example, the terminology is consistent and precise but it took a lot of experimenting for me to grok the importance.
  • Hello all.

    Instead of using the cordic solver, how would one use the MUL instruction to do a 32-bit multiply ?

  • MSwann wrote: »
    Hello all.

    Instead of using the cordic solver, how would one use the MUL instruction to do a 32-bit multiply ?

    So are you avoiding the CORDIC solver because you want signed 32 bit MUL, or in order to get the work done faster?

  • @MSwann Welcome to the forums.
    This thread is for discussion of Tricks and Traps.
    Please start a new thread with the appropriate title and you'll get a lot more help there.
  • Roy,
    Post such questions here.

    To answer the question, the hardware for system timer events fires on msbit rather than rollover. So range is 2^31.

  • I was replying to JonnyMac's post.
    Anyway, seems unfortunate that the waitms/waitus stuff didn't use the full 64bit counter, instead of just the lower 32bits.
  • evanhevanh Posts: 9,693
    edited 2020-03-13 - 03:14:16
    The idea is not to reply in that topic at all. This one is for any discussions.

    When I've made the mistake of replying there in the past I've then asked admin to remove my posts.

  • Roy Eltham wrote: »
    Anyway, seems unfortunate that the waitms/waitus stuff didn't use the full 64bit counter, instead of just the lower 32bits.
    My guess is those functions are using the event hardware in the cog. Not sure how allocation is managed. Anyway, the event hardware also only has a 32-bit compare register. It never got upgraded to match the system timer.

  • My guess is those functions are using the event hardware in the cog. Not sure how allocation is managed. Anyway, the event hardware also only has a 32-bit compare register. It never got upgraded to match the system timer.
    Here's the code from the latest interpreter that handles waitms() and waitus()
    waitus_		getct	w			'get ct now to minimize error
    
    		rdlong	y,#@clkfreq_hub		'get clock frequency
    
    		qmul	y,x			'multiply clock frequency by us/ms
    		getqx	x
    		getqy	y
    
    		cmp	pa,#bc_waitus	wz	'us or ms time unit?
    		mov	z,##1000
    	if_z	mul	z,z
    
    		setq	y			'divide by time unit
    		qdiv	x,z
    		getqx	x
    
    		add	x,w			'add ct
    
    		jmp	#pwct			'do WAITCT
    
    pwct		getct	w		'a b			a: POLLCT(tick)
    		cmpm	w,x	wc	'a b			b: WAITCT(tick)
    	if_c	jmp	#pwct		'| b
    	_ret_	popa	x		'| b
    	_ret_	muxnc	x,_FFFFFFFF	'a
    
  • evanhevanh Posts: 9,693
    edited 2020-03-13 - 04:34:31
    On the other hand, it might just be a signed 32-bit operation in the routine. And not using any hardware beyond the GETCT instruction. Then it'll just be a case of extending the routine to 64-bit operation.

  • I think Chip said he was dead out of space for the interpreter; I wonder if that drove the decision to limit the timing to 32 bits.
  • Another factor is a lack of a 64-bit data type. Right? I vaguely remember a discussion about this back before Chip even started Spin2.

  • JonnyMac wrote: »
    I think Chip said he was dead out of space for the interpreter; I wonder if that drove the decision to limit the timing to 32 bits.

    With more code, it could be achieved. There are 15 identical instructions in the BYTEFILL/WORDFILL/LONGFILL routine that would sure be nice to condense, somehow. Then, we'd have some pennies left over for a 64-bit WAITMS/WAITUS.
  • evanh wrote: »
    The idea is not to reply in that topic at all. This one is for any discussions.

    When I've made the mistake of replying there in the past I've then asked admin to remove my posts.

    Oh oh, I replied in that post. Please remove it.
Sign In or Register to comment.