白小姐四肖必选一肖

芯片IC单片机解密百科

十年专注单片机解密

浅谈ARM汇编与C混合编程的关系

内联汇编即在C中直接使用汇编语句进行编程,使程序可以在C程序中实现C语言白小姐四肖必选一肖不能完成的一些工作,例如,在下面几种情况中必须使用内联汇编或嵌入型汇编

CHENGXUZHONGSHIYONGBAOHESUANSHUYUNSUAN(Saturating Arithmetic)

白小姐四肖必选一肖CHENGXUXUYAODUIXIECHULIQIJINXINGCAOZUO

ZAICCHENGXUZHONGWANCHENGDUICHENGXUZHUANGTAIJICUNQIDECAOZUO

__asm__ __volatile__("asm code":output:input:changed registers);

Note:

白小姐四肖必选一肖SHIYONG__asm__HE__volatile__BIAOSHIBIANYIQIJIANGBUJIANCHAHOUMIANDENEIRONG,ERSHIZHIJIEJIAOJIHUIBIANQI。

RUGUOXIWANGBIANYAQINIYOUHUA,__volatile__KEYIBUJIA

MEIYOUasm codeYEBUNENGSHENGLVE""

MEIYOUQIANMIANDEHEZHONGJIANDEBUFEN,BUKEYIXIANGYINGDESHENGLVE:

白小姐四肖必选一肖MEIYOUchanged BUFEN,BIXUXIANGYINGDESHENGLVE:

ZUIHOUDE;BUNENGSHENGLVE,DUIYUCYUYANLAISHUOZHEISHIYITIAOYUJU

HUIBIANDAIMABIXUFANGZAIYIGEZIFUCHUANNEI,QIEZIFUCHUANZHONGJIANBUNENGZHIJIEANHUICHEHUANXING,KEYIXIECHENGDUOGEZIFUCHUAN,ZHUYIZHONGJIANBUNENGYOURENHEFUHAO,ZHEIYANGJIUHUIJIANGLIANGGEZIFUCHUANHEBINGWEIYIGEZHILINGZHIJIANBIXUYAOHUANXING,HAIKEYISHIYONGtSHIZHILINGZAIHUIBIANZHONGBAOCHIZHENGQI

asm code

白小姐四肖必选一肖"mov r0, r0nt""mov r1,r1nt""mov r2,r2"

output(asm->C)

:"constraint" (variable)

"constraint"用于定义variable的存放位置:
r表示使用任何可用的寄存器
m表示使用变量的内存地址
+可读可写
=只写
白小姐四肖必选一肖&表示该输出操作数不能使用输入部分使用过的寄存器,只能用"+&"或"=&"的方式使用

白小姐四肖必选一肖input(C->asm)

:"constraint" (variable/immediate)

"constraint"用于定义variable的存放位置:
r表示使用任何可用的寄存器(立即数和变量都可以)
m表示使用变量的内存地址
i表示使用立即数

LIZI

int a=100,b=200;int result;__asm__ __volatile__( "mov %0,%3nt" //%0SHIYIGEZHANWEIFU,BIAOSHIresult,ZHIHOUDELEITUI "ldr r0,%1nt" "ldr r1,%2nt" "str r0,%2nt" "str %1,%1nt" :"=r"(result),"+m"(a),"+m"(b) :"i"(123));

ATPCS

白小姐四肖必选一肖ZICHENGXUJIANTONGGUOJICUNQIR0~R3LAICHUANDICANSHU,RUGUOCANSHUDUOYUSIGE,ZEDUOCHUDEBUFENYONGDUIZHANCHUANDI,BEIDIAOYONGDEZICHENGXUZAIFANHUIQIANWUXUHUIFUJICUNQIR0~R3DENEIRONG

白小姐四肖必选一肖ZAIZICHENGXUZHONG,SHIYONGJICUNQIR4~R11LAIBAOCUNJUBUBIANLIANG,RUGUOZAIZICHENGXUZHONGSHIYONGDAOLER4~R11ZHONGDEMOUXIEJICUNQI,ZICHENGXUJINRUSHIBIXUBAOCUNZHEIXIEJICUNQIDEZHI,ZAIFANHUIQIANBIXUHUIFUZHEIXIEJICUNQIDEZHI;DUIYUZICHENGXUZHONGMEIYOUYONGDAODEJICUNQIZEBUBIJINXINGZHEIXIECAOZUO,ZAIThumbCHENGXUZHONG,TONGCHANGZHINENGSHIYONGJICUNQIR4~R7LAIBAOCUNJUBUBIANLIANG

白小姐四肖必选一肖R12YONGZUOZICHENGXUJIANscrtachJICUNQI(YONGYUBAOCUNSP,ZAIHANSHUFANHUISHISHIYONGGAIJICUNQICHUZHAN),JIZUOip

R13YONGZUOSHUJUZHANZHIZHEN,JIZUOsp

R14YONGZUOLIANJIEJICUNQI,JIZUOlr

R15JIZUOCHENGXUJICUNQI,JIZUOpc

XIANGHUDIAOYONG

CHEHUIBIANXIANGHUDIAOYONGYAOTEBIEZHUYIZUNSHOUXIANGYINGDEATPCSGUIZE

CDIAOYONGHUIBIAN

//.c#include extern void strcopy(char* des, const char* src);int main(){ const char* srcstr = "src string"; char desstr[]="des string"; strcopy(desstr, srcstr); return 0;}

白小姐四肖必选一肖;.asm.global strcopystrcopy: ;R0ZHIXIANGMUDEZIFUCHUAN ;R1ZHIXIANGYUANZIFUCHUAN LDRB R2, [R1], #1 ;JIAZAIZIJIEBINGGENGXINYUANZIFUCHUANZHIZHENDIZHI STRB R2, [R0], #1 ;CUNCHUJIJIEBINGGENGXINMUDEZIFUCHUANZHIZHENDIZHI CMP R2, #0 ;PANDUANSHIFOUWEIZIFUCHUANJIEWEI BNE strcopy ;RUGUOBUSHI,CHENGXUTIAOZHUANDAOstrcopyJIXUXUNHUAN MOV pc, ir ;CHENGXUFANHUI

HUIBIANDIAOYONGC

//.cint fcn(int a, int b , int c, int d, int e){ return a+b+c+d+e;}

白小姐四肖必选一肖;.asm;JIASHECHENGXUJINRUfSHI,R0ZHONGDEZHIWEIi;int f(int i){return fcn(i, 2*i, 3*i, 4*i, 5*i);}.text.global _start_start: STR lr, [sp, #-4]! ;BAOCUNFANHUIDIZHIlr ADD R1, R0, R0 ;JISUAN2*i(DI2GECANSHU) ADD R2, R1, R0 ;JISUAN3*i(DI3GECANSHU) ADD R3, R1, R2 ;JISUAN5*i STR R3, [SP, #-4]! ;DI5GECANSHUTONGGUODUIZHANCHUANDI ADD R3, R1, R1 ;JISUAN4*i(DI4GECANSHU) BL fcn ;DIAOYONGCCHENGXU ADD sp, sp, #4 ;CONGDUIZHANZHONGSHANCHUDIWUGECANSHU .end