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* bug in debug
@ 2003-01-04 11:09 Jan Willem Stumpel
  0 siblings, 0 replies; only message in thread
From: Jan Willem Stumpel @ 2003-01-04 11:09 UTC (permalink / raw)
  To: linux-msdos

Freedos:
C:\>debug
=a100
0900:0100 repe scasb
0900:0102 repne scasb
0900:0104
=u100
0900:0100 F3AE          REPE    SCASB
0900:0102 F2AE          REPE    SCASB

MS-DOS 6.00:
C:\>debug
-a100
0A91:0100 repe scasb
0A91:0102 repne scasb
0A91:0104
-u100
0A91:0100 F3            REPZ
0A91:0101 AE            SCASB
0A91:0102 F2            REPNZ
0A91:0103 AE            SCASB

The opcodes F3 and F2 are disassembled by Freedos's DEBUG as if
they are the same. Found this by accident while trying to find out
why Sidekick does not load under Freedos. The reason for that,
apparently, is that Sidekick expects an INT 28 instruction
somewhere in the segment that holds the INDOS flag, and Freedos
doesn't have that. In the location where MS-DOS has INT 28,
Freedos has INT E6. Don't know what that means of course.

Regards, Jan


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