Encoding:

POOL32A

000000

rt

rs

PRECEU.PH.QBR

1101000100

POOL32Axf

111100

6

5

5

10

6

SPECIAL3

011111

0

00000

rt

rd

PRECEU.PH.QBR

11101

ABSQ_S.PH

010010

6

5

5

5

5

6

Format:

PRECEU.PH.QBR rdt, rts

microMIPSDSP

Precision Expand two Unsigned Bytes to Unsigned Halfword Values

Purpose:

Precision Expand two Unsigned Bytes to Unsigned Halfword Values

Expand the precision of two unsigned integer byte values taken from the two right-most elements of a quad byte vector to create two unsigned halfword values.

Description:

rdt = sign_extend(expand_prec8u16(rts15..8) || expand_prec8u16(rts7..0))

The two right-most unsigned integer byte values from the four right-most byte elements in register rts are expanded to create two unsigned halfword values that are then written to destination register rdt. The precision expansion is achieved by pre-pe nding eight most-significant zero bits to each original value to generate each 16 bit halfword value.

Bit 31 of the result is extended into the 32 most-significant bits of the destination register.

Restrictions:

No data-dependent exceptions are possible.

The operands must be values in the specified format. If they are not, the results are UNPREDICTABLE and the values of the operand vectors become UNPREDICTABLE.

Operation:

tempB15..0 = 08 || GPR[rts]15..8
tempA15..0 = 08 || GPR[rts]7..0
GPR[rdt]63..0 = (tempB15)32 || tempB15..0 || tempA15..0

Exceptions:

Reserved Instruction, DSP Disabled