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Watcom ASM + C puzzle, variable has conflicting addresses (Developers)

posted by boeckmann, Aachen, Germany, 01.01.2026, 21:09

> Why would Watcom think "activpg" is at two different addresses? (3461:0C4C
> versus 3461:027C)

Comparing 0x0C4C-0x027C=0x09d0 with the map file indicates that there is some _DATA segment related offset being used while this should be a DGROUP related offset.

As WASM generates group related offsets when encountering something like this:

dgroup group data
data segment
x   db 2
    mov  bh, byte ptr [y]
data ends
end

as shown in the following decoded OMF fixup record (decoded with OMFDUMP, the important part is the "frame method"):

9c FIXUPP16      6 bytes, checksum 7F (valid)
   FIXUP  segment-relative, type 1 (16-bit offset)
          record offset 0005
          frame method F1 (GRPDEF) index 0001 'dgroup'
          target method T4 (SEGDEF) index 0001 'data'


this is indeed puzzling. Can you upload the .OBJ file? Then I can verify via OMFDUMP if the corresponding fixup in the OBJ is correct.

Complete thread:

• Watcom ASM + C puzzle, variable has conflicting addresses - bencollver, 31.12.2025, 23:25 (Developers)
  • Watcom ASM + C puzzle, variable has conflicting addresses - jadoxa, 01.01.2026, 02:06
    • Watcom ASM + C puzzle, variable has conflicting addresses - Rugxulo, 01.01.2026, 03:44
  • Watcom ASM + C puzzle, variable has conflicting addresses - Japheth, 01.01.2026, 09:01
    • Watcom ASM + C puzzle, variable has conflicting addresses - bencollver, 01.01.2026, 16:35
      • Watcom ASM + C puzzle, variable has conflicting addresses - Japheth, 01.01.2026, 18:57
        • Watcom ASM + C puzzle, variable has conflicting addresses - bencollver, 01.01.2026, 21:07
  • Watcom ASM + C puzzle, variable has conflicting addresses - boeckmann, 01.01.2026, 21:09
    • Watcom ASM + C puzzle, variable has conflicting addresses - bencollver, 01.01.2026, 21:32
      • Watcom ASM + C puzzle, variable has conflicting addresses - Japheth, 01.01.2026, 21:51
      • Watcom ASM + C puzzle, variable has conflicting addresses - boeckmann, 01.01.2026, 21:56
        • Watcom ASM + C puzzle, variable has conflicting addresses - boeckmann, 01.01.2026, 21:58
          • Watcom ASM + C puzzle, variable has conflicting addresses - bencollver, 01.01.2026, 22:54
            • Watcom ASM + C puzzle, variable has conflicting addresses - boeckmann, 01.01.2026, 23:26
              • Watcom ASM + C puzzle, variable has conflicting addresses - bencollver, 02.01.2026, 17:42
                • Watcom ASM + C puzzle, variable has conflicting addresses - bencollver, 03.01.2026, 18:09
                  • Watcom ASM + C puzzle, variable has conflicting addresses - ecm, 03.01.2026, 21:23
                  • Watcom ASM + C puzzle, variable has conflicting addresses - bencollver, 16.01.2026, 04:44
              • Watcom ASM + C puzzle, variable has conflicting addresses - Japheth, 04.01.2026, 05:21
                • Watcom ASM + C puzzle, variable has conflicting addresses - rr, 04.01.2026, 11:40
                  • Watcom ASM + C puzzle, variable has conflicting addresses - bencollver, 04.01.2026, 15:31
                    • Watcom ASM + C puzzle, variable has conflicting addresses - Japheth, 04.01.2026, 16:21
  • Watcom ASM + C puzzle, variable has conflicting addresses - samwdpckr, 02.01.2026, 08:50
    • Watcom ASM + C puzzle, variable has conflicting addresses - bretjohn, 08.01.2026, 21:53