Assembler Language Reference

twi or ti (Trap Word Immediate) Instruction

Purpose

Generates a program interrupt when a specified condition is true.

Syntax

Bits	Value
0-5	03
6-10	TO
11-15	RA
16-31	SI

PowerPC
twi	TO, RA, SI

POWER family
ti	TO, RA, SI

See Extended Mnemonics of Fixed-Point Trap Instructions for more information.

Description

The twi and ti instructions compare the contents of general-purpose register (GPR) RA with the sign extended SI field, AND the compared results with TO, and generate a trap-type program interrupt if the result is not 0.

The TO bit conditions are defined as follows.

TO bit	ANDed with Condition
0	Compares Less Than.
1	Compares Greater Than.
2	Compares Equal.
3	Compares Logically Less Than.
4	Compares Logically Greater Than.

The twi and ti instructions have one syntax form and do not affect the Fixed-Point Exception Register or Condition Register Field 0.

Parameters

TO	Specifies TO bits that are ANDed with compare results.
RA	Specifies source general-purpose register for compare.
SI	Specifies sign-extended value for compare.

Examples

The following code generates a Program Interrupt:

# Assume GPR 4 holds 0x0000 0010.
twi 0x4,4,0x10
# A trap type Program Interrupt occurs.

Related Information

Branch Processor .

Fixed-Point Trap Instructions .