Xtensa, added instructions SALT and SALTU, but got Error : Bad Instruction unable to resolve constructor at

[lclevy]

Hi,

I modified ghidra_12.0_PUBLIC\Ghidra\Processors\Xtensa\data\languages\xtensaInstructions.sinc between instructions S32RI and SDCT to handle these instructions:

# SALT - Set AR if Less Than, page 599
:salt ar, as, at is op2 = 0b0111 & op1 = 0b0010 & ar & as & at & op0 = 0 {
    ar = 1;
	if (as s< at)
	  goto inst_next;
	ar = 0;	
}

# SALTU - Set AR if Less Than Unsigned, page 600
:saltu ar, as, at is op2 = 0b0110 & op1 = 0b0010 & ar & as & at & op0 = 0 {
    ar = zext( as < at );	
}

Disassembly is working, but got a red cross before the related line with : Error [Bad Instruction] enable to create constructor at [salt or saltu instruction address] cursor.
Did I miss something ?

Kind regards,
Laurent

[pjsoberoi]

Do you have a test binary? I can take a look.

1. Are you recompiling the .sla file after your changes?

/ghidra_12.0.3_PUBLIC/support$ ./sleigh -a ../Ghidra/Processors/Xtensa/

2. Are you reloading the processor module?

In the Script Manager there is a "ReloadSleighLanguage.java" script. Try running that.

[lclevy]

Hi,
thanks for handling my ticket.

Yes, of course, I'm recompiling

E:\ghidra_12.0_PUBLIC\support>sleigh.bat -a ..\Ghidra\Processors\Xtensa
INFO  Using log config file: jar:file:/E:/ghidra_12.0_PUBLIC/Ghidra/Framework/Generic/lib/Generic.jar!/generic.log4j.xml (LoggingInitialization)
INFO  Using log file: C:\Users\laurent\AppData\Roaming\ghidra\ghidra_12.0_PUBLIC\application.log (LoggingInitialization)
Compiling ..\Ghidra\Processors\Xtensa\data\languages\xtensa_be.slaspec:
WARN  2 NOP constructors found (SleighCompile)
WARN  Use -n switch to list each individually (SleighCompile)
WARN  1 unnecessary extensions/truncations were converted to copies (SleighCompile)
WARN  Use -u switch to list each individually (SleighCompile)

Compiling ..\Ghidra\Processors\Xtensa\data\languages\xtensa_le.slaspec:
WARN  2 NOP constructors found (SleighCompile)
WARN  Use -n switch to list each individually (SleighCompile)
WARN  1 unnecessary extensions/truncations were converted to copies (SleighCompile)
WARN  Use -u switch to list each individually (SleighCompile)

2 languages successfully compiled

Warning above were already here before the addition of Salt and Saltu instructions.

Additionnaly, 2 *.sla files are updated, based on timestamps, below.
I recompiled just before updating this ticket to share command output.

 Directory of E:\ghidra_12.0_PUBLIC\Ghidra\Processors\Xtensa\data\languages

03/04/2026  00:05    <DIR>          .
13/01/2026  18:16    <DIR>          ..
13/01/2026  18:16               603 cust.sinc
13/01/2026  18:16               283 flix.sinc
13/01/2026  18:16             6,828 xtensa.cspec
13/01/2026  18:16               269 xtensa.dwarf
13/01/2026  18:16             1,469 xtensa.ldefs
13/01/2026  18:16               250 xtensa.opinion
13/01/2026  18:16               392 xtensa.pspec
13/01/2026  18:16             9,365 xtensaArch.sinc
03/04/2026  01:47            56,600 xtensaInstructions.sinc
13/01/2026  18:16            13,340 xtensaMain.sinc
06/04/2026  11:54            34,896 xtensa_be.sla
13/01/2026  18:16               278 xtensa_be.slaspec
13/01/2026  18:16               490 xtensa_depbits.sinc
06/04/2026  11:54            34,919 xtensa_le.sla
13/01/2026  18:16               282 xtensa_le.slaspec

And I fully restart Ghidra after each recompilation, yes.

before this modification, salt and saltu instructions were not disassembled at all.
now disassembly is correct, see below:

        e006f7fd e2 c1 50        addi       a14,a1,0x50
        e006f800 70 84 62        saltu      a8,a4,a7                                        
        e006f803 6d 07           mov.n      a6,a7
        e006f805 80 64 93        movnez     a6,a4,a8
...
        e0071a1a 70 48 c0        sub        a4,a8,a7
        e0071a1d 60 55 72        salt       a5,a5,a6
        e0071a20 7a 55           add.n      a5,a5,a7

I verified disassembly is identical to IDA Pro 8.4.

There are tens of salt/saltu instructions successfully disassembled in the binary (I can not share, sorry), after addition in xtensaInstructions.sinc, but each time with "[Error : Bad Instruction unable to resolve constructor at".

Kind regards,
Laurent

[lclevy]

Update: running your script below solved the problem !

In the Script Manager there is a "ReloadSleighLanguage.java" script. Try running that.

Thank you a lot for your help !

[GhidorahRex]

Although the original question has been answered, I think it's worth keeping it open to address the missing salt and saltu instructions