CODEWITHSUNDEEP
iosobjective-c
Fred West
Fred West

Reputation: 25

Detect processor ArmV7 vs ArmV7s. Objective-C

Is it possible in iOS to detect the current processor of the device. The project I am working on requires, programmatically, to check if the processor is ArmV7 or ArmV7s.

Upvotes: 1

Views: 2151

Answers (4)

Pierre Lebeaupin
Pierre Lebeaupin

Reputation: 1113

You don't.

That is, it is not advisable to programmatically detect ARM architecture version support at runtime on iOS. This is the answer I got from an Apple engineer when I specifically asked this question, and given the pitfalls (e.g. what do you do when you get an unexpected value?), I can believe them.

(yes, sometimes the correct answer to an "How do I?" question is "You don't.")

Upvotes: -2

Maxim Kholyavkin
Maxim Kholyavkin

Reputation: 4573

This way:

sysctlbyname("hw.cpusubtype", &value, &length, NULL, 0);

is good, but there are more easy way:

#include <mach-o/ldsyms.h>

int processorType = _mh_execute_header.cputype;
int processorSubtype = _mh_execute_header.cpusubtype;

Although, it shows you which cpu used in compile time for current code..

Upvotes: 0

sbooth
sbooth

Reputation: 16976

I don't know for certain that this will provide the information you'd like but I would try sysctl:

int32_t value = 0;
size_t length = sizeof(value);
sysctlbyname("hw.cpusubtype", &value, &length, NULL, 0);

The values for subtype are in mach/machine.h.

/*
 *  ARM subtypes
 */
#define CPU_SUBTYPE_ARM_ALL             ((cpu_subtype_t) 0)
#define CPU_SUBTYPE_ARM_V4T             ((cpu_subtype_t) 5)
#define CPU_SUBTYPE_ARM_V6              ((cpu_subtype_t) 6)
#define CPU_SUBTYPE_ARM_V5TEJ           ((cpu_subtype_t) 7)
#define CPU_SUBTYPE_ARM_XSCALE      ((cpu_subtype_t) 8)
#define CPU_SUBTYPE_ARM_V7      ((cpu_subtype_t) 9)
#define CPU_SUBTYPE_ARM_V7F     ((cpu_subtype_t) 10) /* Cortex A9 */
#define CPU_SUBTYPE_ARM_V7K     ((cpu_subtype_t) 12) /* Kirkwood40 */

Upvotes: 3

Chris Devereux
Chris Devereux

Reputation: 5473

I'm not aware of any API to check this, but you could perhaps write one yourself by providing v7 and v7s assembler implementations for the same symbol that simply return true or false as required.

Assuming that the v7s implementation will be used if and only if the processor supports v7s, it should work.

Upvotes: 1

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