目前ios的指令集有以下幾種：
-
armv6
- iPhone
- iPhone2
- iPhone3G
- 第一代和第二代iPod Touch
-
armv7
- iPhone4
- iPhone4S
-
armv7s
- iPhone5
- iPhone5C
-
arm64
- iPhone5S
機器對指令集的支持是向下兼容的，因此armv7的指令集是可以運行在iphone5S的，只是效率沒那麼高而已~
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Architecture ： 指你想支持的指令集。
Valid architectures : 指即將編譯的指令集。
Build Active Architecture Only : 只是否只編譯當前適用的指令集。
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現在是2014年初，其實4和4S的用戶還是蠻多的，而iphone3之類的機器幾乎沒有了，所以我們的指令集最低必須基於armv7.
因此,Architecture的值選擇：armv7 armv7s arm64
PS:選arm64時需要最低支持5.1.1:
Convert Your App to a 64-Bit Binary After Updating It for iOS 7
Xcode 5.0.1 can build your app with both 32-bit and 64-bit binaries included. This combined binary requires a minimum deployment target of iOS 5.1.1 or later. The 64-bit binary runs only on 64-bit devices running iOS 7.0.3 and later. If you have an existing app, you should first update your app for iOS 7 and then port it to run on 64-bit processors. By updating it first for iOS 7, you can remove deprecated code paths and use modern practices. If you’re creating a new app, target iOS 7 and compile 32-bit and 64-bit versions of your app.
The architecture for 64-bit apps on iOS is almost identical to the architecture for OS X apps, making it easy to create a common code base that runs in both operating systems. Converting a Cocoa Touch app to 64-bit follows a similar transition process as the
one for Cocoa apps on OS X. Pointers and some common C types change from 32 bits to 64 bits. Code that relies on the NSInteger and CGFloat types
needs to be carefully examined.
Start by building the app for the 64-bit runtime, fixing any warnings that occur as well as searching your code for specific 64-bit issues. For example:
-
Make sure all function calls have a proper prototype.
-
Avoid truncating 64-bit values by accidentally assigning them to a 32-bit data type.
-
Ensure that calculations are performed correctly in the 64-bit version of your app.
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Create data structures whose layouts are identical in the 32-bit and 64-bit versions of your app (such as when you write a data file to iCloud).
1，如果想自己的app在各個機器都能夠最高效率的運行，則需要將Build Active Architecture Only改爲NO,Valid architectures選擇對應的指令集：armv7 armv7s arm64。這個會爲各個指令集編譯對應的代碼，因此最後的 ipa體積基本翻了3倍,Release版本必須NO。
2，如果想讓app體積保持最小，則現階段應該選擇Valid architectures爲armv7,這樣Build Active Architecture Only選YES或NO就無所謂了
