INTEL汇编指令集(3)

BT - Bit Test (386+) Usage: BT dest,src Modifies flags: CF

The destination bit indexed by the source value is copied into the Carry Flag.

Clocks Size Operands 808x 286 386 486 Bytes reg16,immed8 - - 3 3 4-8 mem16,immed8 - - 6 6 4-8 reg16,reg16 - - 3 3 3-7 mem16,reg16 - - 12 12 3-7

BTC - Bit Test with Compliment (386+) Usage: BTC dest,src Modifies flags: CF

The destination bit indexed by the source value is copied into the Carry Flag after being complimented (inverted).

Clocks Size Operands 808x 286 386 486 Bytes reg16,immed8 - - 6 6 4-8 mem16,immed8 - - 8 8 4-8 reg16,reg16 - - 6 6 3-7 mem16,reg16 - - 13 13 3-7

BTR - Bit Test with Reset (386+) Usage: BTR dest,src Modifies flags: CF

The destination bit indexed by the source value is copied into the Carry Flag and then cleared in the destination.

Clocks Size Operands 808x 286 386 486 Bytes reg16,immed8 - - 6 6 4-8 mem16,immed8 - - 8 8 4-8 reg16,reg16 - - 6 6 3-7 mem16,reg16 - - 13 13 3-7

BTS - Bit Test and Set (386+)

Usage: BTS dest,src Modifies flags: CF

The destination bit indexed by the source value is copied into the Carry Flag and then set in the destination.

Clocks Size Operands 808x 286 386 486 Bytes

reg16,immed8 - - 6 6 4-8 mem16,immed8 - - 8 8 4-8 reg16,reg16 - - 6 6 3-7 mem16,reg16 - - 13 13 3-7

CALL - Procedure Call

Usage: CALL destination Modifies flags: None

Pushes Instruction Pointer (and Code Segment for far calls) onto stack and loads Instruction Pointer with the address of proc-name. Code continues with execution at CS:IP.

Clocks

Operands 808x 286 386 486 rel16 (near, IP relative) 19 7 7+m 3 rel32 (near, IP relative) - - 7+m 3 reg16 (near, register indirect) 16 7 7+m 5 reg32 (near, register indirect) - - 7+m 5

mem16 (near, memory indirect) 21+EA 11 10+m 5 mem32 (near, memory indirect) - - 10+m 5 ptr16:16 (far, full ptr supplied) 28 13 17+m 18 ptr16:32 (far, full ptr supplied) - - 17+m 18 ptr16:16 (far, ptr supplied, prot. mode) - 26 34+m 20 ptr16:32 (far, ptr supplied, prot. mode) - - 34+m 20

m16:16 (far, indirect) 37+EA 16 22+m 17 m16:32 (far, indirect) - - 22+m 17 m16:16 (far, indirect, prot. mode) - 29 38+m 20 m16:32 (far, indirect, prot. mode) - - 38+m 20 ptr16:16 (task, via TSS or task gate) - 177 TS 37+TS m16:16 (task, via TSS or task gate) - 180/185 5+TS 37+TS

m16:32 (task) - - TS 37+TS m16:32 (task) - - 5+TS 37+TS ptr16:16 (gate, same privilege) - 41 52+m 35 ptr16:32 (gate, same privilege) - - 52+m 35 m16:16 (gate, same privilege) - 44 56+m 35 m16:32 (gate, same privilege) - - 56+m 35 ptr16:16 (gate, more priv, no parm) - 82 86+m 69 ptr16:32 (gate, more priv, no parm) - - 86+m 69 m16:16 (gate, more priv, no parm) - 83 90+m 69 m16:32 (gate, more priv, no parm) - - 90+m 69 ptr16:16 (gate, more priv, x parms) - 86+4x 94+4x+m 77+4x ptr16:32 (gate, more priv, x parms) - - 94+4x+m 77+4x m16:16 (gate, more priv, x parms) - 90+4x 98+4x+m 77+4x m16:32 (gate, more priv, x parms) - - 98+4x+m 77+4x

CBW - Convert Byte to Word Usage: CBW

Modifies flags: None

Converts byte in AL to word Value in AX by extending sign of AL throughout register AH.

Clocks Size Operands 808x 286 386 486 Bytes none 2 2 3 3 1

CDQ - Convert Double to Quad (386+) Usage: CDQ

Modifies flags: None

Converts signed DWORD in EAX to a signed quad word in EDX:EAX by extending the high order bit of EAX throughout EDX

Clocks Size Operands 808x 286 386 486 Bytes none - - 2 3 1

CLC - Clear Carry

Usage: CLC Modifies flags: CF Clears the Carry Flag.

Clocks Size Operands 808x 286 386 486 Bytes none 2 2 2 2 1

CLD - Clear Direction Flag Usage: CLD Modifies flags: DF

Clears the Direction Flag causing string instructions to increment the SI and DI index registers.

Clocks Size Operands 808x 286 386 486 Bytes none 2 2 2 2 1

CLI - Clear Interrupt Flag (disable) Usage: CLI Modifies flags: IF

Disables the maskable hardware interrupts by clearing the Interrupt flag. NMI's and software interrupts are not inhibited.

Clocks Size Operands 808x 286 386 486 Bytes none 2 2 3 5 1

CLTS - Clear Task Switched Flag (286+ privileged) Usage: CLTS

Modifies flags: None

Clears the Task Switched Flag in the Machine Status Register. This is a privileged operation and is generally used only by operating system code.

Clocks Size Operands 808x 286 386 486 Bytes none - 2 5 7 2

CMC - Complement Carry Flag Usage: CMC Modifies flags: CF

Toggles (inverts) the Carry Flag

Clocks Size Operands 808x 286 386 486 Bytes none 2 2 2 2 1

CMP - Compare

Usage: CMP dest,src

Modifies flags: AF CF OF PF SF ZF

Subtracts source from destination and updates the flags but does not save result. Flags can subsequently be checked for conditions. Clocks Size Operands 808x 286 386 486 Bytes reg,reg 3 2 2 1 2

mem,reg 9+EA 7 5 2 2-4 (W88=13+EA) reg,mem 9+EA 6 6 2 2-4 (W88=13+EA) reg,immed 4 3 2 1 3-4

mem,immed 10+EA 6 5 2 3-6 (W88=14+EA) accum,immed 4 3 2 1 2-3

CMPS - Compare String (Byte, Word or Doubleword) Usage: CMPS dest,src CMPSB CMPSW

CMPSD (386+)

Modifies flags: AF CF OF PF SF ZF

Subtracts destination value from source without saving results. Updates flags based on the subtraction and the index registers (E)SI and (E)DI are incremented or decremented depending on the state of the Direction Flag. CMPSB inc/decrements the index

registers by 1, CMPSW inc/decrements by 2, while CMPSD increments or decrements by 4. The REP prefixes can be used to process

entire data items.

Clocks Size Operands 808x 286 386 486 Bytes

dest,src 22 8 10 8 1 (W88=30)

CMPXCHG - Compare and Exchange

Usage: CMPXCHG dest,src (486+) Modifies flags: AF CF OF PF SF ZF

Compares the accumulator (8-32 bits) with \ If equal the \ with \

Clocks Size Operands 808x 286 386 486 Bytes reg,reg - - - 6 2 mem,reg - - - 7 2 - add 3 clocks if the \

CWD - Convert Word to Doubleword Usage: CWD

Modifies flags: None

Extends sign of word in register AX throughout register DX forming a doubleword quantity in DX:AX.

Clocks Size Operands 808x 286 386 486 Bytes none 5 2 2 3 1

CWDE - Convert Word to Extended Doubleword (386+) Usage: CWDE Modifies flags: None

Converts a signed word in AX to a signed doubleword in EAX by extending the sign bit of AX throughout EAX.

Clocks Size Operands 808x 286 386 486 Bytes none - - 3 3 1

DAA - Decimal Adjust for Addition Usage: DAA

Modifies flags: AF CF PF SF ZF (OF undefined)

Corrects result (in AL) of a previous BCD addition operation. Contents of AL are changed to a pair of packed decimal digits. Clocks Size Operands 808x 286 386 486 Bytes none 4 3 4 2 1

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