Specifications

Intel
®
64 and IA-32 Architectures Software Developer’s Manual Documentation Changes 22
Documentation Changes
BOUND—Check Array Index Against Bounds
Instruction Operand Encoding
...
BSF—Bit Scan Forward
Instruction Operand Encoding
...
BSR—Bit Scan Reverse
Instruction Operand Encoding
...
Opcode Instruction Op/
En
64-bit
Mode
Compat/
Leg Mode
Description
62 /r BOUND r16,
m16&16
AInvalid Valid Check if r16 (array index) is
within bounds specified by
m16&16.
62 /r BOUND r32,
m32&32
AInvalid Valid Check if r32 (array index) is
within bounds specified by
m16&16.
Op/En Operand 1 Operand 2 Operand 3 Operand 4
A ModRM:reg (r) ModRM:r/m (r) NA NA
Opcode Instruction Op/
En
64-bit
Mode
Compat/
Leg Mode
Description
0F BC /r BSF r16, r/m16 A Valid Valid Bit scan forward on r/m16.
0F BC /r BSF r32, r/m32 A Valid Valid Bit scan forward on r/m32.
REX.W + 0F BC BSF r64, r/m64 A Valid N.E. Bit scan forward on r/m64.
Op/En Operand 1 Operand 2 Operand 3 Operand 4
A ModRM:reg (w) ModRM:r/m (r) NA NA
Opcode Instruction Op/
En
64-bit
Mode
Compat/
Leg Mode
Description
0F BD /r BSR r16, r/m16 A Valid Valid Bit scan reverse on r/m16.
0F BD /r BSR r32, r/m32 A Valid Valid Bit scan reverse on r/m32.
REX.W + 0F BD BSR r64, r/m64 A Valid N.E. Bit scan reverse on r/m64.
Op/En Operand 1 Operand 2 Operand 3 Operand 4
A ModRM:reg (w) ModRM:r/m (r) NA NA