ST STM32WB Series Programming Manual

PM0214 Rev 9 71/262
PM0214 The STM32 Cortex-M4 instruction set
261
3.4.2 LDR and STR, immediate offset
Load and Store with immediate offset, pre-indexed immediate offset, or post-indexed
immediate offset.
Syntax
op{type}{cond} Rt, [Rn {, #offset}]; immediate offset
op{type}{cond} Rt, [Rn, #offset]!; pre-indexed
op{type}{cond} Rt, [Rn], #offset; post-indexed
opD{cond} Rt, Rt2, [Rn {, #offset}]; immediate offset, two words
opD{cond} Rt, Rt2, [Rn, #offset]!; pre-indexed, two words
opD{cond} Rt, Rt2, [Rn], #offset; post-indexed, two words
Where:
• ‘op’ is either LDR (load register) or STR (store register)
• ‘type’ is one of the following:
B: Unsigned byte, zero extends to 32 bits on loads
SB: Signed byte, sign extends to 32 bits (LDR only)
H: Unsigned halfword, zero extends to 32 bits on loads
SH: Signed halfword, sign extends to 32 bits (LDR only)
—: Omit, for word
• ‘cond’ is an optional condition code (see Conditional execution on page 65)
• ‘Rt’ is the register to load or store
• ‘Rn’ is the register on which the memory address is based
• ‘offset’ is an offset from Rn. If offset is omitted, the address is the contents of Rn
• ‘Rt2’ is the additional register to load or store for two-word operations
Operation
LDR instructions load one or two registers with a value from memory. STR instructions store
one or two register values to memory.
Load and store instructions with immediate offset can use the following addressing modes:
Offset addressing
The offset value is added to or subtracted from the address obtained from the register
Rn. The result is used as the address for the memory access. The register Rn is
unaltered. The assembly language syntax for this mode is: [Rn, #offset].
Pre-indexed addressing
The offset value is added to or subtracted from the address obtained from the register
Rn. The result is used as the address for the memory access and written back into the
register Rn. The assembly language syntax for this mode is: [Rn, #offset]!
Post-indexed addressing
The address obtained from the register Rn is used as the address for the memory
access. The offset value is added to or subtracted from the address, and written back
into the register Rn. The assembly language syntax for this mode is: [Rn], #offset.

ST STM32WB Series Specifications

General

Brand	ST
Model	STM32WB Series
Category	Computer Hardware
Language	English