Assembler User Guide

Load immediate 32-bit values to a register using LDR Rd, =const

ARM Compiler toolchain v5.02 for µVision Using the Assembler

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Load immediate 32-bit values to a register using LDR Rd, =const

The LDR Rd,=const pseudo-instruction can construct any 32-bit numeric value in a single instruction. You can use this pseudo-instruction to generate constants that are out of range of the MOV and MVN instructions.

The LDR pseudo-instruction generates the most efficient single instruction for the specified immediate value:

If the immediate value can be constructed with a single MOV or MVN instruction, the assembler generates the appropriate instruction.
If the immediate value cannot be constructed with a single MOV or MVN instruction, the assembler:
- places the value in a literal pool (a portion of memory embedded in the code to hold constant values)
- generates an LDR instruction with a PC-relative address that reads the constant from the literal pool.
For example:
```
    LDR      rn, [pc, #offset to literal pool]
                          ; load register n with one word
                          ; from the address [pc + offset]
```
You must ensure that there is a literal pool within range of the LDR instruction generated by the assembler.

Assembler User Guide

Load immediate 32-bit values to a register using LDR Rd, =const

Load immediate 32-bit values to a register using LDR Rd, =const

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