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Assembler Language Reference

sradi (Shift Right Algebraic Double Word Immediate) Instruction

Purpose

Algebraically shift the contents of a general purpose register right by the number of bits specified by the immediate value. Place the result of the operation in another general purpose register.

Syntax

PowerPC
sradi RA, RS, SH (Rc=0)
sradi. RA, RS, SH (Rc=1)

Description

The contents of general purpose register (GPR) RS are shifted right SH bits. Bits shifted out of position 63 are lost. Bit 0 of GPR RS is replicated to fill the vacated positions on the left. The result is placed into GPR RA. XER[CA] is set if GPR RS is negative and any 1 bits are shifted out of position 63; otherwise XER[CA] is cleared. A shift amount of zero causes GPR RA to be set equal to GPR RS, and XER[CA] to be cleared.

Note that the sradi instruction, followed by addze, can by used to divide quickly by 2**n. The setting of the CA bit, by sradi, is independent of mode.

Other registers altered:

Parameters

RA Specifies target general-purpose register for the result of the operation.
RS Specifies source general-purpose register containing the operand for the shift operation.
SH Specifies shift value for operation.

Implementation

This instruction is defined only for 64-bit implementations. Using it on a 32-bit implementation will cause the system illegal instruction error handler to be invoked.


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