Motorola CPU32 Bedienungsanleitung Seite 81

  • Herunterladen
  • Zu meinen Handbüchern hinzufügen
  • Drucken
  • Seite
    / 646
  • Inhaltsverzeichnis
  • LESEZEICHEN
  • Bewertet. / 5. Basierend auf Kundenbewertungen
Seitenansicht 80
Instruction Set Summary
3-10 M68000 FAMILY PROGRAMMER’S REFERENCE MANUAL MOTOROLA
3.1.5 Bit Manipulation Instructions
BTST, BSET, BCLR, and BCHG are bit manipulation instructions. All bit manipulation
operations can be performed on either registers or memory. The bit number is specified
either as immediate data or in the contents of a data register. Register operands are 32 bits
long, and memory operands are 8 bits long. Table 3-6 summarizes bit manipulation
operations; Z refers to the zero bit of the CCR.
3.1.6 Bit Field Instructions
The M68000 family architecture supports variable-length bit field operations on fields of up
to 32 bits. The BFINS instruction inserts a value into a bit field. BFEXTU and BFEXTS
extract a value from the field. BFFFO finds the first set bit in a bit field. Also included are
instructions analogous to the bit manipulation operations: BFTST, BFSET, BFCLR, and
BFCHG. Table 3-7 summarizes bit field operations.
NOTE: All bit field instructions set the CCR N and Z bits as shown for BFTST before performing the specified operation.
Table 3-6. Bit Manipulation Operation Format
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 3-7. Bit Field Operation Format
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
Seitenansicht 80
1 2 ... 76 77 78 79 80 81 82 83 84 85 86 ... 645 646

Kommentare zu diesen Handbüchern

Keine Kommentare