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ARM INSTRUCTION SET S3C2440A RISC MICROPROCESSOR
3-32
ASSEMBLER SYNTAX
<LDR|STR>{cond}{B}{T} Rd,<Address>
where:
LDR Load from memory into a register
STR Store from a register into memory
{cond} Two-character condition mnemonic. See Table 3-2.
{B} If B is present then byte transfer, otherwise word transfer
{T} If T is present the W bit will be set in a post-indexed instruction, forcing non-privileged
mode for the transfer cycle. T is not allowed when a pre-indexed addressing mode is
specified or implied.
Rd An expression evaluating to a valid register number.
Rn and Rm Expressions evaluating to a register number. If Rn is R15 then the assembler will
subtract 8 from the offset value to allow for ARM920T pipelining.
In this case base write-back should not be specified.
<Address>can be:
1 An expression which generates an address:
The assembler will attempt to generate an instruction using the PC as a base and a
corrected immediate offset to address the location given by evaluating the expression.
This will be a PC relative, pre-indexed address. If the address is out of range, an error
will be generated.
2 A pre-indexed addressing specification:
[Rn] offset of zero
[Rn,<#expression>]{!} offset of <expression> bytes
[Rn,{+/-}Rm{,<shift>}]{!} offset of +/- contents of index register, shifted
by <shift>
3 A post-indexed addressing specification:
[Rn],<#expression> offset of <expression> bytes
[Rn],{+/-}Rm{,<shift>} offset of +/- contents of index register, shifted as
by <shift>.
<shift> General shift operation (see data processing instructions) but you cannot specify the shift
amount by a register.
{!} Writes back the base register (set the W bit) if! is present.