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[sdcc-devel] [ sdcc-Bugs-3361386 ] --no-std-crt0 linking problem on -mz80
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From: SourceForge.net <no...@so...> - 2011-07-11 17:56:34
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Bugs item #3361386, was opened at 2011-07-10 06:34 Message generated for change (Comment added) made by spth You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=100599&aid=3361386&group_id=599 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: linker Group: None Status: Open Resolution: None Priority: 5 Private: No Submitted By: stewartjk (stewartjk) Assigned to: Nobody/Anonymous (nobody) Summary: --no-std-crt0 linking problem on -mz80 Initial Comment: Compiler versions tried are 3.0.0 and latest snapshot. When I use the --no-std-crt0 option in a -mz80 build and supply my own crt0.rel file linking does not appear to be working correctly even when the crt0.rel file is a copy of the original z80 crt0.rel. The problem I see is the call to initialise the data array points to the C9 return code after the array initialisation code. In the attachment I have provided some simple test code and the good and bad binary images of the code produced. To work around the problem I have to remove the --no-std-crt0 option and copy my customised crt0.rel file to the /usr/local/share/sdcc/lib/z80/ directory. Problem build: sdcc -mz80 --no-std-crt0 --data-loc 0 testcrt0.rel crt0.rel Build that works sdcc -mz80 --data-loc 0 testcrt0.rel I'm new to sdcc so apologies if I'm doing something incorrect. ---------------------------------------------------------------------- >Comment By: Philipp Klaus Krause (spth) Date: 2011-07-11 19:56 Message: I can reproduce the problem when using sdcc -mz80 --no-std-crt0 --data-loc 0 testcrt0.rel crt0.rel I cannot reproduce the problem when using sdcc -mz80 --no-std-crt0 --data-loc 0 crt0.rel testcrt0.rel Beware that for the latter command the output files, including .ihx and .map are named differently. Philipp ---------------------------------------------------------------------- Comment By: stewartjk (stewartjk) Date: 2011-07-10 18:13 Message: The attached map file was produced with this command line: sdcc -mz80 --no-std-crt0 --code-loc 0x1000 --data-loc 0x0800 testcrt0.rel crt0.rel ---------------------------------------------------------------------- Comment By: stewartjk (stewartjk) Date: 2011-07-10 15:51 Message: As can be seen the code and data locations don't change even when swapping the addresses... Swapped rel ordering: sdcc -mz80 --no-std-crt0 --code-loc 0x0800 --data-loc 0x1000 crt0.rel testcrt0.rel 00000100 31 FF FF CD 24 08 CD 00 10 C3 0D 10 00000800 FF FF FF FF FF FF FF FF 21 00 08 36 12 21 01 08 36 12 23 36 12 23 36 12 23 36 12 23 36 12 23 36 00000820 12 23 36 12 C9 00001000 3E 30 F5 33 CD 13 10 33 C9 3E 02 CF C9 3E 00 CF 76 18 FD 21 02 00 39 6E 3E 01 CF C9 6B 3E 01 CF 00001020 C9 Swapped rel ordering address locations: sdcc -mz80 --no-std-crt0 --code-loc 0x1000 --data-loc 0x0800 crt0.rel testcrt0.rel 00000100 31 FF FF CD 24 08 CD 00 10 C3 0D 10 00000800 FF FF FF FF FF FF FF FF 21 00 08 36 12 21 01 08 36 12 23 36 12 23 36 12 23 36 12 23 36 12 23 36 00000820 12 23 36 12 C9 00001000 3E 30 F5 33 CD 13 10 33 C9 3E 02 CF C9 3E 00 CF 76 18 FD 21 02 00 39 6E 3E 01 CF C9 6B 3E 01 CF 00001020 C9 Normal rel ordering and swapped address locations: sdcc -mz80 --no-std-crt0 --code-loc 0x1000 --data-loc 0x0800 testcrt0.rel crt0.rel 00000100 31 FF FF CD 24 08 CD 00 10 C3 0D 10 00000800 FF FF FF FF FF FF FF FF 21 00 08 36 12 21 01 08 36 12 23 36 12 23 36 12 23 36 12 23 36 12 23 36 00000820 12 23 36 12 C9 00001000 3E 30 F5 33 CD 13 10 33 C9 3E 02 CF C9 3E 00 CF 76 18 FD 21 02 00 39 6E 3E 01 CF C9 6B 3E 01 CF 00001020 C9 ---------------------------------------------------------------------- Comment By: stewartjk (stewartjk) Date: 2011-07-10 15:32 Message: Apologies for the double post before... Also I meant to say: "The code goes into 0x0800 fine but the data initialisation still wants to call the 0xC9 return instruction at 0x1008." ---------------------------------------------------------------------- Comment By: Philipp Klaus Krause (spth) Date: 2011-07-10 15:32 Message: Could you try 1) Swapping the order of testcrt0.rel and crt0.rel in your command line 2) Using a higher value for --code-loc than for --data-loc 3) Both of the above And provide the .map files? Currently this looks like a bug in the default crt0 to me: .area _GSINIT gsinit:: .area _GSFINAL ret will only work if the linker sees the crt0 first, placing the gsinit:: at the start of the gsinit section, and the initialization from the other files after that, before the ret. If the linker sees the other filees first, it will first place the initialization ocde, effectively jumping to the ret at the end of the initialization. Philipp ---------------------------------------------------------------------- Comment By: stewartjk (stewartjk) Date: 2011-07-10 15:19 Message: I've tried all sorts of settings with code and data locations, here is one with some settings that seem sensible to me but still produces the same problem: sdcc -mz80 --no-std-crt0 --code-loc 0x0800 --data-loc 0x1000 testcrt0.rel crt0.rel The code goes into 0x0800 fine but the data initialisation still wants to call the 0xC9 return instruction at 0x1024. It should actually be calling 0x100d instead. 00000100 31 FF FF CD 24 10 CD 00 08 C3 0D 08 00001000 FF FF FF FF FF FF FF FF 21 00 10 36 12 21 01 10 36 12 23 36 12 23 36 12 23 36 12 23 36 12 23 36 00001020 12 23 36 12 C9 It would appear that the --no-std-crt0 option insists that you have to init the data yourself but this is not what the manual states, I just want to tell the compiler to use my own crt0.rel file and it should not be bypassing the initialisation of the data. ---------------------------------------------------------------------- Comment By: stewartjk (stewartjk) Date: 2011-07-10 15:17 Message: I've tried all sorts of settings with code and data locations, here is one with some settings that seem sensible to me but still produces the same problem: sdcc -mz80 --no-std-crt0 --code-loc 0x0800 --data-loc 0x1000 testcrt0.rel crt0.rel The code goes into 0x0800 fine but the data initialisation still wants to call the 0xC9 return instruction at 0x1024. It should actually be calling 0x100d instead. 00000100 31 FF FF CD 24 10 CD 00 08 C3 0D 08 00001000 FF FF FF FF FF FF FF FF 21 00 10 36 12 21 01 10 36 12 23 36 12 23 36 12 23 36 12 23 36 12 23 36 00001020 12 23 36 12 C9 It would appear that the --no-std-crt0 option insists that you have to init the data yourself but this is not what the manual states, I just want to tell the compiler to use my own crt0.rel file and it should not be bypassing the initialisation of the data. ---------------------------------------------------------------------- Comment By: Philipp Klaus Krause (spth) Date: 2011-07-10 14:40 Message: The workaround probably just changes the order, in which the linker sees the files. Try setting --data-loc and --code-loc to more sensible values. In particular, do not tell the linker to place the any of those sections at the same place as the crt0. Your example tells the linker to place both the data and part of crt0 at address zero (the crt0 has an .org 0 and .org 0x100). The safe way is probaly to try rather high --data-loc and --code-loc first, and then reduce it to calim back unused space between crt0 and them. Please report back if this fixes your problem. Philipp ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=100599&aid=3361386&group_id=599 |