Branch Conditional (bc) Instruction

Concept

The Branch Conditional (bc) instruction is a processor branch operation whose behavior can be influenced by the Condition Register (CR). Automated architectural-knowledge extraction, using a decision-tree classifier over collected instruction samples, has identified the specific operand encodings and CTR values that determine when a bc instruction is affected by CR.

First seen 7/9/2026

Last seen 7/9/2026

Evidence 2 chunks

Wiki v1

WIKI

Branch Conditional (bc) Instruction

Overview

The Branch Conditional (bc) instruction is a conditional branch operation found in instruction-set architectures. Its execution path can be governed by flag values held in the Condition Register (CR), meaning that depending on operand encodings (and, in special cases, the CTR register contents), the instruction either always reads and is affected by the CR, or only sometimes is.

READ FULL ARTICLE →

NEIGHBORHOOD

No graph connections found for this entity yet. It may appear in future ingestion runs.

explore full graph →

RELATIONSHIPS

2 connections

Condition Register (CR) uses → 97% 2e

The bc instruction's behavior is affected by the CR (Condition Register).

Instruction Opcode mentions → 88% 1e

The bc instruction has an opcode that is part of its attributes used in classification.

LINKED ENTITIES

2 links

Condition Register (CR) USES Extracted graph relationship

Instruction Opcode MENTIONS Extracted graph relationship

CITATIONS

6 sources

6 citations — click to expand

[1] The bc (branch conditional) instruction can be affected by the Condition Register (CR), and this dependence was automatically determined by a classifier over collected instruction samples. Automatic identification of information useful for generation-based ...

[2] When opcode is bc and bo.data is in {0x0,0x1,0x8,0x9} and CTR is not 0x0000000000000001, the instruction is always (100%) affected by CR (209/209 attempts). Automatic identification of information useful for generation-based ...

[3] When opcode is bc and bo.data is in {0x4,0x5,0x6,0x7,0xC,0xD,0xE,0xF}, the instruction is always (100%) affected by CR (952/952 attempts). Automatic identification of information useful for generation-based ...

[4] For opcode bc in all other encodings, CR-affected behavior occurs sometimes (47%, 1193/2486 attempts). Automatic identification of information useful for generation-based ...

[5] CR-affected status is determined by toggling a CR flag, re-executing the instruction on a simulator, and comparing simulated machine states — divergence indicates the instruction reads and is affected by the flag. Automatic identification of information useful for generation-based ...

[6] Sample rows demonstrate bc execution with varying CTR, MSR, bi.data, bo.data, and CR.Affected outcomes, supporting the classifier's identified rules. Automatic identification of information useful for generation-based ...