Excerpts for 116B (224KB)
Excerpts for 116B (224KB)
Excerpts for 116B (224KB)
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Addressing Capabilities<br />
2.2.7 Address Register Indirect with Index (8-Bit Displacement) Mode<br />
This addressing mode requires one extension word that contains an index register indicator<br />
and an 8-bit displacement. The index register indicator includes size and scale in<strong>for</strong>mation.<br />
In this mode, the operand is in memory. The operand’s address is the sum of the address<br />
register’s contents; the sign-extended displacement value in the extension word’s low-order<br />
eight bits; and the index register’s sign-extended contents (possibly scaled). The user must<br />
specify the address register, the displacement, and the index register in this mode.<br />
.<br />
GENERATION:<br />
ASSEMBLER SYNTAX:<br />
EA MODE FIELD:<br />
EA REGISTER FIELD:<br />
NUMBER OF EXTENSION WORDS:<br />
EA = (An) + (Xn) + d8<br />
(d 8 ,An, Xn.SIZE*SCALE)<br />
110<br />
REG. NO.<br />
1<br />
31<br />
0<br />
ADDRESS REGISTER<br />
CONTENTS<br />
DISPLACEMENT<br />
INDEX REGISTER<br />
31<br />
7 0<br />
SIGN EXTENDED<br />
INTEGER<br />
31 0<br />
SIGN-EXTENDED VALUE<br />
+<br />
SCALE<br />
OPERAND POINTER<br />
SCALE VALUE<br />
X<br />
31 0<br />
CONTENTS<br />
POINTS TO<br />
+<br />
MEMORY<br />
OPERAND<br />
MOTOROLA M68000 FAMILY PROGRAMMER’S REFERENCE MANUAL 2-9
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