Encoding:

Format:

SLLV rd, rt, rs 

Purpose:

Shift Word Left Logical Variable

To left-shift a word by a variable number of bits.

Description:

 GPR[rd] = GPR[rt] << GPR[rs]

The contents of the low-order 32-bit word of GPR rt are shifted left, inserting zeros into the emptied bits. The resulting word is sign-extended and placed in GPR rd. The bit-shift amount is specified by the low-order 5 bits of GPR rs.

Restrictions:

None

Operation:

s = GPR[rs]4..0
temp = GPR[rt](31-s)..0 || 0s
GPR[rd] = sign_extend(temp)

Exceptions:

None

Programming Notes:

The input operand does not have to be a properly sign-extended word value to produce a valid sign-extended 32-bit result. The result word is always sign-extended into a 64-bit destination register; this instruction with a zero shift amount truncates a 64-bit value to 32 bits and sign-extends it.