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8. Instruction Set Reference
NII-PRG | 2018.04.18
Exceptions
Instruction Type
Instruction Fields
31
30
29
A
15
14
13
0x1f
8.5.67. mulxsu
Instruction
Operation
Assembler Syntax
Example
Description
Usage
Exceptions
Instruction Type
Instruction Fields
31
30
29
A
15
14
13
0x17
8.5.68. mulxuu
Instruction
Operation
28
27
26
25
12
11
10
9
28
27
26
25
12
11
10
9
Unimplemented instruction
R
= Register index of operand rA
A
= Register index of operand rB
B
= Register index of operand rC
C
Bit Fields
24
23
22
21
B
8
7
6
5
0
multiply extended signed/unsigned
rC
((signed) rA) x ((unsigned) rB))
mulxsu rC, rA, rB
mulxsu r6, r7, r8
Treating rA as a signed integer and rB as an unsigned
integer,
multiplies rA times rB, and stores the 32
mulxsu
high-order bits of the product to rC.
Nios II processors that do not implement the
instruction cause an unimplemented instruction exception.
can be used as part of the calculation of a 128-bit
mulxsu
product of two 64-bit signed integers. Given two 64-bit
integers, each contained in a pair of 32-bit registers, (S1 :
U1) and (S2 : U2), their 128-bit product is: (U1 x U2) +
((S1 x U2) << 32) + ((U1 x S2) << 32) + ((S1 x S2) <<
64). The
and
mulxsu
mul
the two 64-bit products S1 x U2 and U1 x S2.
Unimplemented instruction
R
= Register index of operand rA
A
= Register index of operand rB
B
= Register index of operand rC
C
Bit Fields
24
23
22
21
B
8
7
6
5
0
multiply extended unsigned/unsigned
rC
((unsigned) rA) x ((unsigned) rB))
20
19
18
17
C
4
3
2
1
0x3a
63..32
mulxsu
instructions are used to calculate
20
19
18
17
C
4
3
2
1
0x3a
63..32
continued...
Nios II Processor Reference Guide
16
0x1f
0
16
0x17
0
215
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