Encoding:

EXTEND

11110

imm 10:5

imm 15:11

ADDIUSP

00000

rx

0

000

imm 4:0

5

6

5

5

3

3

5

Format:

ADDIU rx, sp, immediate

MIPS16e

Add Immediate Unsigned Word (3-Operand, SP-Relative, Extended)

Purpose:

Add Immediate Unsigned Word (3-Operand, SP-Relative, Extended)

To add a constant to the stack pointer.

Description:

GPR[rx] = GPR[sp] + immediate

The 16-bit immediate is sign-extended and then added to the contents of GPR 29 to form a 32-bit result. The result is placed in GPR rx.

No integer overfl w exception occurs under any circumstances.

Restrictions:

None

Operation:

temp = GPR[29] + sign_extend(immediate
GPR[Xlat(rx)] = temp

Exceptions:

None

Programming Notes:

The term "unsigned" in the instruction name is a misnomer;this operation is 32-bit modulo arithmetic that does not trap on overfl w. It is appropriate for unsigned arithmetic, such as address arithmetic, or integer arithmetic environments that ignore overfl w, such as C language arithmetic.