From: "Paul Gilmartin" <[email protected]>
Sent: Thursday, 9 September 2010 12:35 AM
On Sep 8, 2010, at 05:39, robin wrote:
From: "Tony Harminc"
Sent: Wednesday, 8 September 2010 9:20 AM
It's also how "classic" (base & displacement) addressing arithmetic,
which we all know deals only with unsigned values, can subtract.
Classic base-displacement atithmetic is always addition,
never subtraction.
Ahem.
LH R1,=H'-4096'
USING -4096,R1
LA R2,*
LA R3,-4(,R2)
What does R3 now address?
That is irrelevant.
You seem to be confused about how the hardware computes
an address.
The displacement is treated as an UNSIGNED integer,
which is ADDED to the content of the base register.
This caused a great deal of debate on this list several years
ago. Very few contributors got it right.
You were not one of the few, apparently.
