CVS commit: [netbsd-11] src/sys/arch/mvme68k/mvme68k

["Martin Husemann" <martin%netbsd.org@localhost>]

Module Name:    src
Committed By:   martin
Date:           Sat Nov 22 14:16:42 UTC 2025

Modified Files:
        src/sys/arch/mvme68k/mvme68k [netbsd-11]: locore.s

Log Message:
Pull up following revision(s) (requested by thorpej in ticket #98):

        sys/arch/mvme68k/mvme68k/locore.s: revision 1.145

In the Lbrdmatch loop, fix the number of bytes the pointer is advanced
when a match is not found (code was using 18, correct number is 10).

Explainer:
The board type entries consist of 4 shorts + 1 long for a total of 12
bytes.  When comparing the board ID, the pointer is advanced meaning
that there are 10 bytes left to skip in the case of a non-match.

As for why the old code was using 18 (0x12) bytes, a comment that says
"Each entry is 20-2 bytes long" provides a clue: if the CPU type, MMU
type, and FPU type entries were longs, each entry would in fact be 18
bytes -- and maybe this was the case in the distant past.  However, it
still would be wrong to advance 18 bytes because of the auto-increment
used during the compare.

scw@ is a smart guy and I'm certain this worked at some point, but I'm
not going to go and do the archeology needed to figure out exactly when
this broke.  If you happened to have an MVME147 (first entry in the board
type list) or booted a single-type kernel, it would work fine.  But If you
had an MVME16x or MVME17x, then this small error would bite your behind
when booting GENERIC.

PR port-mvme68k/59780


To generate a diff of this commit:
cvs rdiff -u -r1.131 -r1.131.4.1 src/sys/arch/mvme68k/mvme68k/locore.s

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.