PM0215 datasheet(58/91 Pages) STMICROELECTRONICS

No. de pieza	PM0215

Descripción Electrónicos	STM32F0xxx Cortex-M0 programming manual

PDF	91 Pages

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Fabricante Electrónico	STMICROELECTRONICS [STMicroelectronics]

Página de inicio	http://www.st.com

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58 / 91 page

The STM32 Cortex-M0 instruction set

PM0215

58/91

Doc ID 022979 Rev 1

3.5.9

TST

Test bits.

Syntax

TST Rn, Rm

where:

●

‘Rn’ is the register holding the first operand

●

‘Rm’ is the register to test against.

Operation

This instruction tests the value in a register against another register. It updates the condition

flags based on the result, but does not write the result to a register.

The TST instruction performs a bitwise AND operation on the value in Rn and the value in

Rm. This is the same as the ANDS instruction, except that it discards the result.

To test whether a bit of Rn is 0 or 1, use the TST instruction with a register that has that bit

set to 1 and all other bits cleared to 0.

Restrictions

In these instructions, Rn and Rm must only specify R0-R7.

Condition flags

This instruction:

●

Updates the N and Z flags according to the result

●

Does not affect the C or V flag

Examples

TST

R0, R1

; Perform bitwise AND of R0 value and R1 value,

; condition code flags are updated but result is discarded

PM0215 Datasheet(PDF) 58 Page - STMicroelectronics