[B2-devel] MOVE16 (Ax)+,(Ay)+

[Lauri P. <lpe...@ni...>]

Hello,

One of the Motorola errata files ("040de.txt" in my Motorola
archive, "DOCUMENTATION CLARIFICATION FOR MC68040, MC68EC040 &
MC68LC040") states:

"MOVE16 (Ax)+,(Ay)+ where Ax=Ay is functionally the same as
 MOVE16 (Ax),(Ay)+.  The address register only gets incremented
 once and the line is copied over itself instead of copied into
 the next line."

So in op op_f620_0(), instead of:
 m68k_areg(regs, srcreg) += 16;\r\n");
 m68k_areg(regs, dstreg) += 16;\r\n");

we should probably do:
 if(srcreg != dstreg) m68k_areg(regs, srcreg) += 16;\r\n");
 m68k_areg(regs, dstreg) += 16;\r\n");

I know that this is a degenerate case, but Murphy's Law states
that some weird program relies on this particular behavior :)

Lauri