Bug in mpx+s2asm+tasm

Bug in mpx+s2asm+tasm

Post by James R. Whi » Sat, 24 Mar 1990 05:35:36



There is a * bug with mpx+s2asm+tasm.
Lines 461,462 of mpx88.x (in the save routine for interrupts):
        seg     cs
        jmp     (bx)
are converted by the posted s2asm to:
        jmp     cs:(bx)
which is the same as:
        jmp     cs:bx

Now tasm figures that since a segment override prefix is meaningless here,
what you really mean is:
        jmp     cs:[bx]
which is a completely different instruction. What's more, tasm does this
quietly, without warning you. Thus, when you try to boot minix the
machine jumps to some odd location when it tries to process an interrupt.

The fix is to delete the segment override prefix. Then tasm works OK.