android在armv4t中跑

最新推荐文章于 2025-07-23 20:37:05 发布

flymachine

最新推荐文章于 2025-07-23 20:37:05 发布

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分类专栏： Linux Kernel Android 文章标签： android assembly reference exchange branch user

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本文介绍了如何处理ARM架构中特定的未定义指令，包括BLX、CLZ、LDRD等，并提供了替换宏定义和内联汇编的具体实现方式。

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http://benno.id.au/blog/2007/11/21/android-neo1973通过这篇文章。决定使用处理未定义指令这种方式。因为最近学了驱动嘛。这是一个练手的机会。

有下面这些指令：（试试吧）

Opcode	Desription	[PDF ] Page Number	C	ASM
BLX(1)	Branch, Link, and Exchange	166	N/A (Unused in Android)	N/A (Unused in Android)
BLX(2)	Branch, Link, and Exchange	168	User:Cfriedt 20081028 Remove from inline assembly with something like #ifdef HAVE_BLX ... (inline asm) ... #else ... (inline asm with equivalent blx code, as shown to the right) ... #endif	User:Cfriedt 20081028 Substitute with a macro reference such as #ifdef HAVE_BLX #define BLX(a) / blx a #else #define BLX(a) / mov pc,lr / bx a #endif
CLZ	Count Leading Zeros	175	User:Cfriedt 20081028 Remove from inline assembly with something like #ifdef HAVE_CLZ ... (inline asm) ... #else ... (inline asm with equivalent clz code, as shown to the right) ... #endif	User:Cfriedt 20081029 #ifdef HAVE_CLZ #define CLZ(Rd,Rm) / clz Rd,Rm #else #define CLZ(Rd,Rm) / ... #endif ... CLZ(Rd,Rm)
LDRD	Load Registers Doubleword	200	User:Cfriedt 20081028 Substitute different inline assembly code with something like #ifdef HAVE_LDRD ... (inline asm) ... #else ... (inline asm with ldrd substituted) ... #endif	User:Cfriedt 20081028 Substitute with a macro reference such as #ifdef HAVE_LDRD #define LDRD(a,b) / ldrd a,b #else #define LDRD(a,b) / ... #endif
PLD	Preload Data	240	User:Cfriedt 20081028 Remove from inline assembly with something like #ifdef HAVE_PLD ... (inline asm) ... #else ... (inline asm with pld removed) ... #endif	User:Cfriedt 20081028 Remove or substitute with a macro reference such as #ifdef HAVE_PLD #define PLD(a,b) / pld a,b #else #define PLD(a,b) #endif ... PLD(r0,#0)
SMLA<x><y>	Signed Multiply-Accumulate	291
SMLAL<x><y>	Signed Multiply Accumulate Long	298
SMLAW<y>	Signed Multiply-Accumulate Word	302
SMUL<x><y>	Signed Multiply	316
SMULW<y>	Signed Multiply Word	320
QADD	Saturating Add	242
QDADD	Saturating Double and Add	249
QDSUB	Saturating Double and Subtract	251
QSUB	Saturating Subtract	253
STRD	Store Registers Doubleword	349	User:Cfriedt 20081028 Substitute different inline assembly code with something like #ifdef HAVE_STRD ... (inline asm) ... #else ... (inline asm without strd) ... #endif