Instruction Set Summary
MOTOROLA MC68030 USER’S MANUAL 3-9
3.2.6 Bit Field Operations
The MC68030 supports variable-length bit field operations on fields of up to 32 bits. The bit
field insert (BFINS) instruction inserts a value into a bit field. Bit field extract unsigned
(BFEXTU) and bit field extract signed (BFEXTS) extract a value from the field. Bit field find
first one (BFFFO) finds the first bit that is set in a bit field. Also included are instructions that
are analogous to the bit manipulation operations; bit field test (BFTST), bit field test and set
(BFSET), bit field test and clear (BFCLR), and bit field test and change (BFCHG). Table 3–
6 is a summary of the bit field operations.
NOTE: All bit field instructions set the N and Z bits as shown for BFTST before performing the specified operation.
Table 3-5. Bit Manipulation Operations
Instruction Operand Syntax Operand Size Operation
BCHG Dn,〈ea〉
#〈data〉,ea
8, 32
8, 32
∼ (〈bit number〉 of destination) → Z → bit of destination
BCLR Dn,〈ea〉
#〈data〉,ea
8, 32
8, 32
∼ (〈bit number〉 of destination) → Z;
— 0 → bit of destination
BSET Dn,〈ea〉
#〈data〉,〈ea〉
8, 32
8, 32
∼ (〈bit number〉 of destination) → Z;
— 1 → bit of destination
BTST Dn,〈ea〉
#〈data〉,ea
8, 32
8, 32
∼ (〈bit number〉 of destination) → Z
Table 3-6. Bit Field Operations
Instruction Operand Syntax Operand Size Operation
BFCHG 〈ea〉 {offset:width} 1 — 32 ∼ Field → Field
BFCLR 〈ea〉 {offset:width} 1 — 32 0's → Field
BFEXTS 〈ea〉 {offset:width},Dn 1—32 Field → Dn; Sign Extended
BFEXTU 〈ea〉 {offset:width},Dn 1 — 32 Field → Dn; Zero Extended
BFFFO 〈ea〉 {offset:width},Dn 1 — 32 Scan for first bit set in field; offset → Dn
BFINS Dn,〈ea〉 {offset:width} 1 — 32 Dn → Field
BFSET 〈ea〉 {offset:width} 1 — 32 1's → Field
BFTST 〈ea〉 {offset:width} 1 — 32 Field MSB → N; ∼ (OR of all bits in field) → Z
To Next Page
Loading...
Need help?
General
