Assembler Syntax
mulxuu rC, rA, rB
Example
mulxuu r6, r7, r8
Description
Treating rA and rB as unsigned integers,
mulxuu
multiplies
rA times rB and stores the 32 high-order bits of the product
to rC.
Nios II processors that do not implement the
mulxuu
instruction cause an unimplemented instruction exception.
Usage
Use
mulxuu
and
mul
to compute the 64-bit product of two
32-bit unsigned integers. Furthermore,
mulxuu
can be used
as part of the calculation of a 128-bit product of two 64-bit
signed integers. Given two 64-bit signed 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
mulxuu
and
mul
instructions are used to calculate the 64-bit product
U1 x U2.
mulxuu
also can be used as part of the calculation of a 128-
bit product of two 64-bit unsigned integers. Given two 64-
bit unsigned integers, each contained in a pair of 32-bit
registers, (T1 : U1) and (T2 : U2), their 128-bit product is
(U1 x U2) + ((U1 x T2) << 32) + ((T1 x U2) << 32) + ((T1
x T2) << 64). The
mulxuu
and
mul
instructions are used to
calculate the four 64-bit products U1 x U2, U1 x T2, T1 x
U2, and T1 x T2.
Exceptions
Unimplemented instruction
Instruction Type
R
Instruction Fields
A
= Register index of operand rA
B
= Register index of operand rB
C
= Register index of operand rC
Bit Fields
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
A
B
C
0x07
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0x07
0
0x3a
8.5.69. nextpc
Instruction
get address of following instruction
Operation
rC ← PC + 4
Assembler Syntax
nextpc rC
Example
nextpc r6
Description
Stores the address of the next instruction to register rC.
Usage
A relocatable code fragment can use
nextpc
to calculate
the address of its data segment.
nextpc
is the only way to
access the PC directly.
Exceptions
None
Instruction Type
R
Instruction Fields
C
= Register index of operand rC
8. Instruction Set Reference
NII-PRG | 2018.04.18
Nios II Processor Reference Guide
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