Generating assembly in large multi-unit projects

allenhuffman · Posted: Tue Feb 25, 2020 11:21 am

When I do a simple, small test program, I see each file represented by assembly source in the .lst file.

But in a large project here, we haven't been able to find the source in all files. I finally made a simple test program and called it from main():

temtronic · Posted: Tue Feb 25, 2020 11:35 am

Allen you sure do find things that I've never seen since PCM v2.453 !

As for why the asm code is 'far, far away', that's explained in the manual FAQ or Q&A section. In a nutshell, the single pass compiler has to fit code into available 'bank' spaces and can't overflow. It will rearrange functions to try to maximize complete code in a bank. You'll see posts about 'Out of ROM' with lots of ROM actually left, but you can't put two 5KB functions into one 8KB bank. You also can't 'split' a function over 2 banks.
At least not long time ago.
If you want a listing to appear in 'code space' sequence, import to a program that will sort based on memory address. I did that 4 decades ago while cutting Z80 assembler.

allenhuffman · Posted: Tue Feb 25, 2020 11:39 am

I found a reference to the out-of-order .lst in the FAQ (something I'd been wondering about):

http://www.ccsinfo.com/faq.php?page=lst_out_of_order

It does make the assembly rather useless when you can't (easily?) figure out what asm belong to what code. Smile

In this case, I'm trying to track down the printfs() that are printing the wrong string, to look at the good vs bad asm and see what the difference is.
_________________
Allen C. Huffman, Sub-Etha Software (est. 1990) http://www.subethasoftware.com
Embedded C, Arduino, MSP430, ESP8266/32, BASIC Stamp and PIC24 programmer.
http://www.whywouldyouwanttodothat.com ?

temtronic · Posted: Tue Feb 25, 2020 11:54 am

gee Allen, I started PICkin when all PICs had quartz skylights and erase meant time for another 15 minute coffee break Laughing

PICs are easy to code in assembler, only 35 instructions, far less than Z80 or 8080s. Sadly today's PICs have more fuses than instructions.
Surely there's some 'fancy' Windoze 'ap' you can import and sort the listing ? Even the old DOS 'sort.exe' might work... Wink

allenhuffman · Posted: Tue Feb 25, 2020 11:55 am

temtronic · Posted: Tue Feb 25, 2020 1:00 pm

I was under the impression you wanted the listing to be in same order the physical PIC memory is, not 'splattered all over the place'....

allenhuffman · Posted: Tue Feb 25, 2020 1:45 pm

temtronic · Posted: Tue Feb 25, 2020 4:28 pm

I think it goes back to the 'try to fill each bank with complete code' algorithm for the compiler.
Initially it may try to do it inline but decide it can't fit a complete function or 'chunk' of contiguous code into a bank. It may then attempt to do a 'best fit' approach. I know in the past you could NOT have a function cross a boarder between banks, especilally tables !
Over the years PICs have got bigger so I assume CCS has more 'smarts' in the compiler to figure all this stuff out. To complicate things, there's more 'features' and 'C' compatibilty to deal with. Originally CCS C wasn't 'official' C ( whatever that means.....)

allenhuffman · Posted: Wed Feb 26, 2020 1:30 pm

temtronic · Posted: Wed Feb 26, 2020 1:43 pm

Well.. there's no such thing as a 'normal C compiler', never has, never will be. Every mfr of a compiler has their 'quirks' and of course there is no official, died in the wool, cast in granite C language. Everything 'evolves'.
CCS does a darn good job of getting THEIR version of 'C' to run in PICs and obviously CCS C won't run in an Ardunio.
I'm not a trained C programmer, rather I've muddled through, self taught since PCM 2.534+-. My programs may not be coded in 'official C' practices, but they work.