MOTOROLA
M68000 FAMILY PROGRAMMER’S REFERENCE MANUAL
8-1
SECTION 8
INSTRUCTION FORMAT SUMMARY
This section contains a listing of the M68000 family instructions in binary format. It is listed
in opcode order for the M68000 family instruction set.
8.1 INSTRUCTION FORMAT
The following paragraphs present a summary of the binary encoding fields.
8.1.1 Coprocessor ID Field
This field specifies which coprocessor in a system is to perform the operation. When using
directly supported floating-point instructions for the MC68040, this field must be set to one.
8.1.2 Effective Address Field
This field specifies which addressing mode is to be used. For some operations, there are
hardware-enforced restrictions on the available addressing modes allowed.
8.1.3 Register/Memory Field
This field is common to all arithmetic instructions. A zero in this field indicates a register-to-
register operation, and a one indicates an < ea > -to-register operation.
8.1.4 Source Specifier Field
This field is common to all artihmetic instructions. The value of the register/memory (R/M)
field affects this field,s definition. If R/M = 0, specifies the source floating-point data register
(FPDR). If R/M = 1, specifies the source operand data format.
000 —Long-Word Integer (L)
001 —Single-Precision Real (S)
010 —Extended-Precision Real (X)
011 — Packed-Decimal Real (P)
100 —Word Integer (W)
101 —Double-Precision Real (D)
110 — Byte Integer (B)
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