ST STM32F3 Series User Manual

PM0214 Rev 10 63/262
PM0214 The STM32 Cortex-M4 instruction set
261
LSR
Logical shift right by n bits moves the left-hand 32-n bits of the Rm register to the right by n
places, into the right-hand 32-n bits of the result. And it sets the left-hand n bits of the result
to 0 (see Figure 14).
You can use the LSR #n operation to divide the value in the Rm register by 2
n
, if the value is
regarded as an unsigned integer.
When the instruction is LSRS or when LSR #n is used in operand2 with the instructions
MOVS, MVNS, ANDS, ORRS, ORNS, EORS, BICS, TEQ or TST, the carry flag is updated
to the last bit shifted out, bit[n-1], of the Rm register.
Note: 1 If n is 32 or more, then all the bits in the result are cleared to 0.
2 If n is 33 or more and the carry flag is updated, it is updated to 0.
Figure 14. LSR #3
LSL
Logical shift left by n bits moves the right-hand 32-n bits of the Rm register to the left by n
places, into the left-hand 32-n bits of the result. And it sets the right-hand n bits of the result
to 0 (see Figure 15: LSL #3).
The LSL #n operation can be used to multiply the value in the Rm register by 2
n
, if the value
is regarded as an unsigned integer or a two’s complement signed integer. Overflow can
occur without warning.
When the instruction is LSLS or when LSL #n, with non-zero n, is used in operand2 with the
instructions MOVS, MVNS, ANDS, ORRS, ORNS, EORS, BICS, TEQ or TST, the carry flag
is updated to the last bit shifted out, bit[32-n], of the Rm register. These instructions do not
affect the carry flag when used with LSL #0.
Note: 1 If n is 32 or more, then all the bits in the result are cleared to 0.
2 If n is 33 or more and the carry flag is updated, it is updated to 0.
Figure 15. LSL #3
MSv39679V1
Carry
Flag
031 5 4 3 2 1
00
0
MSv39678V1
031 5 4 3 2 1
Carry
Flag
00
0

ST STM32F3 Series Specifications

General

Series	STM32F3
Core	ARM Cortex-M4
Max CPU Frequency	72 MHz
Operating Voltage	2.0 V to 3.6 V
GPIO Pins	Up to 80
Timers	Advanced-control, general-purpose, basic timers
ADC	12-bit
DAC	12-bit
Communication Interfaces	USART, SPI, I2C, CAN, USB
Operating Temperature	-40°C to 85°C
Package	LQFP, UFQFPN, WLCSP

Summary

Introduction

1 About this document

1.1 Typographical conventions

Conventions used in the document for formatting text and code elements.

1.2 List of abbreviations for registers

Abbreviations used in register descriptions.

1.3 About the STM32 Cortex-M4 processor and core peripherals

Overview of the processor's features and integrated peripherals.

2 The Cortex-M4 processor

2.1 Programmers model

Describes the programmer's model, processor modes, privilege levels, and stacks.

2.2 Memory model

Details the processor memory map, access behavior, and bit-banding features.

2.3 Exception model

Explains the exception model, states, types, handlers, and priorities.

2.4 Fault handling

Details fault types, escalation, status registers, and lockup.

2.5 Power management

Describes mechanisms for entering and waking up from sleep modes.

3 The STM32 Cortex-M4 instruction set

3.1 Instruction set summary

Overview of the instruction set and supported instructions.

3.2 CMSIS intrinsic functions

CMSIS intrinsic functions for generating Cortex-M4 instructions.

3.3 About the instruction descriptions

Explains how instruction descriptions are presented in the document.

3.4 Memory access instructions

Details instructions for accessing memory.

3.5 General data processing instructions

Covers general-purpose data processing instructions.

3.6 Multiply and divide instructions

Describes instructions for multiplication and division operations.

3.7 Saturating instructions

Explains instructions that perform saturating arithmetic.

3.8 Packing and unpacking instructions

Instructions for packing and unpacking data.

3.9 Bitfield instructions

Instructions for operating on bitfields within registers.

3.10 Floating-point instructions

Instructions for floating-point operations using the FPU.

3.11 Miscellaneous instructions

Other Cortex-M4 instructions not categorized elsewhere.

4 Core peripherals

4.1 About the STM32 Cortex-M4 core peripherals

Overview of core peripherals and their memory map in the PPB.

4.2 Memory protection unit (MPU)

Details the MPU's functionality for memory protection and region management.

4.3 Nested vectored interrupt controller (NVIC)

Describes the NVIC's support for interrupts, priorities, and tail-chaining.

4.4 System control block (SCB)

Provides system implementation info and control for exceptions.

4.5 SysTick timer (STK)

Details the SysTick timer, its registers, and usage hints.

4.6 Floating point unit (FPU)

Explains the FPU's functionality, registers, and enabling.

5 Revision history