#include <arm/machine_cpuid.h>
arm/machine_cpuid.h
CPU feature identification
structarm_feature_bits_t
| uint32_t:4 | arm_32bit_isa | |
| uint32_t:4 | arm_thumb_ver | |
| uint32_t:4 | arm_jazelle | |
| uint32_t:4 | arm_thumb2 | |
| uint32_t:16 | reserved |
typedefarm_feature_bits_t
typedef struct arm_feature_bits_t arm_feature_bits_t;
unionarm_feature0_reg_t
| arm_feature_bits_t | field | |
| uint32_t | value |
typedefarm_feature0_reg_t
typedef union arm_feature0_reg_t arm_feature0_reg_t;
structsyscp_ID_instructions_feat_1_reg
Register 0, subtype 21: Instruction Set Features #1
| uint32_t:4 | endianness_support | |
| uint32_t:4 | exception_1_support | |
| uint32_t:4 | exception_2_support | |
| uint32_t:4 | sign_zero_ext_support | |
| uint32_t:4 | if_then_support | |
| uint32_t:4 | immediate_support | |
| uint32_t:4 | interworking_support | |
| uint32_t:4 | jazelle_support |
typedefsyscp_ID_instructions_feat_1_reg
typedef struct syscp_ID_instructions_feat_1_reg syscp_ID_instructions_feat_1_reg;
unionarm_isa_feat1_reg
| uint32_t | value | |
| syscp_ID_instructions_feat_1_reg | field |
typedefarm_isa_feat1_reg
typedef union arm_isa_feat1_reg arm_isa_feat1_reg;
functionmachine_read_isa_feat1
arm_isa_feat1_reg machine_read_isa_feat1(void)
▾
claude-fable-5, 2026-08-24 · not from Apple sources · verified against xnu osfmk/arm/machine_cpuid.h
Returns the contents of the CPU's Instruction Set Attribute Register 1 as an arm_isa_feat1_reg union, whose bit-fields report endianness, exception handling, sign/zero extension, if-then (IT), immediate, interworking, and Jazelle instruction support. Legacy 32-bit ARM CPU identification interface; no implementation is present in current arm64 xnu sources.
unionarm_cpuid_id_dfr0
ID_DFR0
| unnamed struct at Kernel/arm/machine_cpuid.h:70:2 | debug_feature | |||||||||||||||||||
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| uint32_t | value | |||||||||||||||||||
typedefarm_cpuid_id_dfr0
typedef union arm_cpuid_id_dfr0 arm_cpuid_id_dfr0;
unionarm_debug_dbgdidr
DBGDIDR
| unnamed struct at Kernel/arm/machine_cpuid.h:83:2 | debug_id | ||||||||||||||||||||||||||||||||||
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| uint32_t | value | ||||||||||||||||||||||||||||||||||
typedefarm_debug_dbgdidr
typedef union arm_debug_dbgdidr arm_debug_dbgdidr;
structarm_debug_info_t
| boolean_t | memory_mapped_core_debug | |
| boolean_t | coprocessor_core_debug | |
| uint32_t | num_watchpoint_pairs | |
| uint32_t | num_breakpoint_pairs |
typedefarm_debug_info_t
typedef struct arm_debug_info_t arm_debug_info_t;