Rev. 1.50, 10/04, page 27 of 448
Addressing
Mode
Instruction
Format Effective Address Calculation Method
Calculation
Formula
PC-relative
with
displacement
@(disp:8, PC) Effective address is PC + 4 with 8-bit displacement
disp added. After disp is zero-extended, it is
multiplied by 2 (word), or 4 (longword), according
to the operand size. With a longword operand,
the lower 2 bits of PC are masked.
PC
H'FFFF FFFC
PC + 4 + disp
× 2
or PC &
H'FFFF FFFC
+ 4 + disp × 4
+
4
2/4
×
+
&
*
disp
(zero-extended)
*
With longword operand
Word: PC + 4
+ disp × 2 →
EA
Longword:
PC & H'FFFF
FFFC + 4 +
disp × 4 → EA
PC-relative disp:8 Effective address is PC + 4 with 8-bit displacement
disp added after being sign-extended and
multiplied by 2.
2
+
×
disp
(sign-extended)
4
+
PC
PC + 4 + disp × 2
PC + 4 + disp
× 2 → Branch-
Target
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