Altera Nios II User Manual page 228

8–48
div
Operation:
Assembler Syntax:
Example:
Description:
Usage:
Exceptions:
Instruction Type:
Instruction Fields:
31 30 29 28 27 26 25
A
Nios II Processor Reference Handbook
rC ← rA ÷ rB
div rC, rA, rB
div r6, r7, r8
Treating rA and rB as signed integers, this instruction divides rA by rB and then stores the
integer portion of the resulting quotient to rC. After attempted division by zero, the value of rC
is undefined. There is no divide-by-zero exception. After dividing –2147483648 by –1, the
value of rC is undefined (the number +2147483648 is not representable in 32 bits). There is
no overflow exception.
Nios II processors that do not implement the div instruction cause an unimplemented
instruction exception.
Remainder of Division:
If the result of the division is defined, then the remainder can be computed in rD using the
following instruction sequence:
div rC, rA, rB
mul rD, rC, rB
sub rD, rA, rD
Division error
Unimplemented instruction
R
A = Register index of operand rA
B = Register index of operand rB
C = Register index of operand rC
24 23 22 21 20 19 18 17
B C
# The original div operation
# rD = remainder
16 15 14 13 12 11 10
0x25
Chapter 8: Instruction Set Reference
Instruction Set Reference
9 8 7 6 5 4 3 2
0 0x3a
February 2014 Altera Corporation
divide
1 0