Excalibur electronic A-MNL-NIOSPROG-01.1 用户手册
Altera Corporation
49
32323232
32-Bit Instruction Set
2
3
2
-B
it In
st
st
ru
ctio
n
n
Se
t
t
EXT8d
Byte-Extract (Dynamic)
Operation:
RA
← (0x00.00.00 :
bn
RA) where n = RB[1..0]
Assembler Syntax:
EXT8d %rA,%rB
Example:
LD %g4,[%i0] ; get 32 bits from [%i0 & 0xFF.FF.FF.FC]
EXT8d %g4,%i0 ; extract the particular byte at %i0
Description:
Extracts one of the four bytes in RA. The byte to-be-extracted is chosen by bits
1..0 of RB (byte 3 being the most-significant byte of RA). The selected byte is
1..0 of RB (byte 3 being the most-significant byte of RA). The selected byte is
written into bits 7..0 of RA, and the more-significant bits 31..8 are set to zero.
Condition Codes:
Flags: Unaffected
Instruction Format:
RR
Instruction Fields:
A = Register index of operand RA
B = Register index of operand RB
B = Register index of operand RB
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0
1
0
0
1
1
B
A
N
V
Z
C
−
−
−
−