デバイスが32bitなのか64bitなのかチェックする ref: http://qiita.com/roothybrid7/items/3cfeb2837cb468bcab13

file0.txt

if (sizeof(int *) == 4) {
    // 32bit
} else if (sizeof(int *) == 8) {
    // 64bit
}
// others

file1.txt

// UIDevice+Hardware.h
typedef NS_ENUM(NSUInteger, DeviceArchitecture) {
    DeviceArchitectureUnknown,
    DeviceArchitecture32Bit,
    DeviceArchitecture64Bit,
};

@interface UIDevice (Hardware)

- (DeviceArchitecture)cpuArchitecture;

@end

// UIDevice+Hardware.m
#import "UIDevice+Hardware.h"

@implementation UIDevice (Hardware)

- (DeviceArchitecture)cpuArchitecture {
    if (sizeof(int *) == 4) {
        return DeviceArhictecture32Bit;
    } else if (sizeof(int *) == 8) {
        return DeviceArchitecture64Bit;
    }
    return DeviceArchitectureUnknown;
}

@end