Assemblers and Linkers

The pic ports use gputils (both the ports and gputils are currently unmaintained)

Other ports use sdas (by default), which is a fork of an older asxxxx, then released under a GPL-compatible license. Later asxxxx changed to a GPL-incompatible license, and sdas and asxxxx started diverging. When asxxxx switched to GPL, the differences were substantial enough to make a merge non-trivial. Today, e.g. both sdas and asxxxx have independently-developed stm8 ports.

Some ports (z80 and related) have some limited support for using other assemblers.

The sdas situation is far from optimal. Possible ways forward include:

• Merge current asxxxx into sdas

• Switch to GNU binutils. However, GNU binutils does not support all SDCC targets. This might still be an option for some ports. It would also make it easier to get the link-time dead code elimination¹ requested by many users.

¹ Apparently some users put unused functions into their source files, and expect the linker to optimize them out (they also don't want to use .lib libraries, for which sdas can do it already).

This is a list of the current state, extensions, differences with 5.40 and progress:

Assemblers missing in upstream:

• all aspdk
• astlcs90

Assemblers being close to upstream state:

• as6500
• as6808
• as8051
• as8xcxxx

asrab:

• extension: .r4k (Rabbit 4000 support)

asz80:

• extension: .zxn (ZX Spectrum Next), .ez80 (Zilog eZ80)
• extension: undocumented instructions
• lacks: .8080 (Intel 8080), .8085 (Intel 8085), .8085x (extended instructions)

ASxxxx core: (incomplete)

• extension: (partial?) gcc-like error output
• extension: supports .optsdcc
• lacking .bank and .end directives

ASLINK: (incomplete)

• extension: supports O
• asldgb: translates virtual addresses for ihx and noi output
• lacks: bank information

Upstreaming progress:

• sdasgb extensions should be available in Version 5.40 Update 6

Tips:

• compile with --no-optsdcc-in-asm to be able to assemble with upstream ASxxxx
• linux: convert zip to linux and build upstream with make -C asxmak/linux/build/ (read readme.txt)
• assembler=as6500; diff -d -B -w --suppress-blank-empty ~/projects/sdcc-code/sdcc/sdas/${assembler} ~/projects/asxxxx/${assembler} | less can be used for listing the differences

[Ragozini Arturo]

The current sdasz80 is lacking of undocumented z80 instructions due to a bug. More in general its z80 mnemonics do not respect the common conventions used by Zilog and by other assemblers. This is a problem when I try to include my existing ASM code (audio players, math libraries, graphic libraries) in the SDCC projects.
Maybe replacing sdasz80 with something more advanced and standard could make easier the integration of the existing code base in the SDCC projects.

[Sebastian Riedel]

It is indeed relevant for “possible ways forward include”

-mz80 claims to support z80asm and gas, but that would be obviously be without built-in peep hole rules.
Switching to a completely different assembler might require splitting z80/z180/z80n/ez80 from rabbit/sm83/tlcs90. Definitely for peep hole rules. (They currently share general rules)

More should be discussed in [feature-requests:#791]