mtfsb0

Move To FPSCR Bit 0

mtfsb0 BT

Clears a specific bit in the FPSCR.

Encoding

Binary Layout

63

0:5

BT

6:10

/

11:15

/

16:20

70

21:30

/

31

 

Format X-form

Opcode 0xFC00008C

Extension Floating-Point

Operands

• BT
  Bit Index

Example

mtfsb0 0

Registers Altered

FPSCR

Related

More in Floating-Point

Reference

View in PowerISA v3.1C Specification ↗ OPF Power ISA v3.1C

Description

Clears (sets to 0) the FPSCR bit specified by BT. The FPSCR bits are numbered 0-31. Clearing certain FPSCR bits (e.g., exception bits or mode flags) can alter the behavior of subsequent floating-point operations.

Operation

FPSCR[BT] ← 0

Programming Note

The mtfsb0 instruction sets a specific bit in the FPSCR register to the value of the U field. It's commonly used for controlling floating-point exceptions and status flags. Be cautious when altering the FX bit, as it affects exception handling. This instruction operates at user privilege level.