lha (Load Half Algebraic) instruction
Purpose
Loads a halfword of data from a specified location in memory into a general-purpose register and copies bit 0 of the halfword into the remaining 16 bits of the general-purpose register.
Syntax
| Bits | Value |
|---|---|
| 0 - 5 | 42 |
| 6 - 10 | RT |
| 11 - 15 | RA |
| 16 - 31 | D |
Description
The lha instruction loads a halfword of data from a specified location in memory, addressed by the effective address (EA), into bits 16-31 of the target general-purpose register (GPR) RT and copies bit 0 of the halfword into bits 0-15 of GPR RT.
If GPR 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 GPR RA is 0, then the EA is D.
The lha instruction has one syntax form and does not affect the Fixed-Point Exception Register or Condition Register Field 0.
Parameters
| Item | Description |
|---|---|
| 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 halfword of data into bits 16-31 of GPR 6 and copies bit 0 of the halfword into bits 0-15 of GPR 6:
.csect data[rw]
storage: .short 0xffff
# Assume GPR 5 contains the address of csect data[rw].
.csect text[pr]
lha 6,storage(5)
# GPR 6 now contains 0xffff ffff.