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AIX Version 4.3 Assembler Language Reference

lbz (Load Byte and Zero) Instruction

Purpose

Loads a byte of data from a specified location in memory into a general-purpose register and sets the remaining 24 bits to 0.

Syntax

lbz RT,D(RA)

Description

The lbz instruction loads a byte in storage addressed by the effective address (EA) into bits 24-31 of the target general-purpose register (GPR) RT and sets bits 0-23 of GPR RT to 0.

If RA is not 0, the EA is the sum of the contents of GPR RA and D, a 16-bit, signed two's complement integer sign-extended to 32 bits. If RA is 0, then the EA is D.

The lbz instruction has one syntax form and does not affect the Fixed-Point Exception Register or Condition Register Field 0.

Parameters

RT Specifies target general-purpose register where result of operation is stored.
D 16-bit, signed two's complement integer sign-extended to 32 bits for EA calculation.
RA Specifies source general-purpose register for EA calculation.

Examples

The following code loads a byte of data from a specified location in memory into GPR 6 and sets the remaining 24 bits to 0:

.csect data[rw]
storage:  .byte 'a
# Assume GPR 5 contains the address of csect data[rw].
.csect text[pr]
lbz 6,storage(5)
# GPR 6 now contains 0x0000 0061.

Related Information

Fixed-Point Processor.

Fixed-Point Load and Store Instructions.


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