{
char i=0;
printf("i=%d", i);
char j=0;
printf("j=%d", j);
char k=0;
printf("k=%d", k);
char l=0;
printf("l=%d", l);
char m=0;
printf("m=%d", m);
char n=0;
printf("n=%d", n);
char o=0;
printf("o=%d", o);
char p=0;
printf("p=%d", p);
char q=0;
printf("q=%d", q);
char r=0;
printf("r=%d", r);
char s=0;
printf("s=%d", s);
char t=0;
printf("t=%d", t);
char str[3]="Jim";
printf("str=%s", str);
}
0x70007724: e92d5fff ._-. PUSH {r0-r12,lr}
0x70007728: e3a04000 .@.. MOV r4,#0 //從R4寄存器開始使用，每定義一個變量使用一個寄存器
0x7000772c: e1a01004 .... MOV r1,r4 //將剛剛定義並初始化的變量(r4中)取出，放到r1中
0x70007730: e28f0fce .... ADR r0,{pc}+0x340 ; 0x70007a70 //取出"i=%d"字符串的地址到r0中
0x70007734: fa00027f .... BLX __2printf ; 0x70008138 //調用printf函數，函數調用的傳參規則是：func(r0,r1,r2,r3)
0x70007738: e3a05000 .P.. MOV r5,#0
0x7000773c: e1a01005 .... MOV r1,r5
0x70007740: e28f0e33 3... ADR r0,{pc}+0x338 ; 0x70007a78
0x70007744: fa00027b {... BLX __2printf ; 0x70008138
0x70007748: e3a06000 .`.. MOV r6,#0
0x7000774c: e1a01006 .... MOV r1,r6
0x70007750: e28f0fca .... ADR r0,{pc}+0x330 ; 0x70007a80
0x70007754: fa000277 w... BLX __2printf ; 0x70008138
0x70007758: e3a07000 .p.. MOV r7,#0
0x7000775c: e1a01007 .... MOV r1,r7
0x70007760: e28f0e32 2... ADR r0,{pc}+0x328 ; 0x70007a88
0x70007764: fa000273 s... BLX __2printf ; 0x70008138
0x70007768: e3a08000 .... MOV r8,#0
0x7000776c: e1a01008 .... MOV r1,r8
0x70007770: e28f0fc6 .... ADR r0,{pc}+0x320 ; 0x70007a90
0x70007774: fa00026f o... BLX __2printf ; 0x70008138
0x70007778: e3a09000 .... MOV r9,#0
0x7000777c: e1a01009 .... MOV r1,r9
0x70007780: e28f0e31 1... ADR r0,{pc}+0x318 ; 0x70007a98
0x70007784: fa00026b k... BLX __2printf ; 0x70008138
0x70007788: e3a0a000 .... MOV r10,#0
0x7000778c: e1a0100a .... MOV r1,r10
0x70007790: e28f0fc2 .... ADR r0,{pc}+0x310 ; 0x70007aa0
0x70007794: fa000267 g... BLX __2printf ; 0x70008138
0x70007798: e3a0b000 .... MOV r11,#0 //寄存器r11中存放定義的新變量
0x7000779c: e1a0100b .... MOV r1,r11
0x700077a0: e28f0c03 .... ADR r0,{pc}+0x308 ; 0x70007aa8
0x700077a4: fa000263 c... BLX __2printf ; 0x70008138
0x700077a8: e3a00000 .... MOV r0,#0 //寄存器已經不夠用了，需要通過堆棧來存儲新定義的變量。
0x700077ac: e58d000c .... STR r0,[sp,#0xc]
0x700077b0: e28f0fbe .... ADR r0,{pc}+0x300 ; 0x70007ab0
0x700077b4: e59d100c .... LDR r1,[sp,#0xc]
0x700077b8: fa00025e ^... BLX __2printf ; 0x70008138
0x700077bc: e3a00000 .... MOV r0,#0
0x700077c0: e58d0008 .... STR r0,[sp,#8]
0x700077c4: e28f0fbb .... ADR r0,{pc}+0x2f4 ; 0x70007ab8
0x700077c8: e59d1008 .... LDR r1,[sp,#8]
0x700077cc: fa000259 Y... BLX __2printf ; 0x70008138
0x700077d0: e3a00000 .... MOV r0,#0
0x700077d4: e58d0004 .... STR r0,[sp,#4]
0x700077d8: e28f0e2e .... ADR r0,{pc}+0x2e8 ; 0x70007ac0
0x700077dc: e59d1004 .... LDR r1,[sp,#4]
0x700077e0: fa000254 T... BLX __2printf ; 0x70008138
0x700077e4: e3a00000 .... MOV r0,#0
0x700077e8: e58d0000 .... STR r0,[sp,#0]
0x700077ec: e28f0fb5 .... ADR r0,{pc}+0x2dc ; 0x70007ac8
0x700077f0: e59d1000 .... LDR r1,[sp,#0]
0x700077f4: fa00024f O... BLX __2printf ; 0x70008138
0x700077f8: e8bd9fff .... POP {r0-r12,pc}
$d //這裏是常量表區
0x70007a40: 202d492d -I- DCD 539838765
0x70007a44: 5049752d -uIP DCD 1346991405
0x70007a48: 7325202d - %s DCD 1931812909
0x70007a4c: 00000d0a .... DCD 3338
0x70007a50: 41203a50 P: A DCD 1092631120
0x70007a54: 49205050 PP I DCD 1226854480
0x70007a58: 2074696e nit DCD 544500078
0x70007a5c: 202e2e2e ... DCD 539897390
0x70007a60: 00000000 .... DCD 0
0x70007a64: 73626577 webs DCD 1935828343
0x70007a68: 65767265 erve DCD 1702261349
0x70007a6c: 000d0a72 r... DCD 854642
0x70007a70: 64253d69 i=%d DCD 1680162153
0x70007a74: 00000000 .... DCD 0
0x70007a78: 64253d6a j=%d DCD 1680162154
0x70007a7c: 00000000 .... DCD 0
0x70007a80: 64253d6b k=%d DCD 1680162155
0x70007a84: 00000000 .... DCD 0
0x70007a88: 64253d6c l=%d DCD 1680162156
0x70007a8c: 00000000 .... DCD 0
0x70007a90: 64253d6d m=%d DCD 1680162157
0x70007a94: 00000000 .... DCD 0
0x70007a98: 64253d6e n=%d DCD 1680162158
0x70007a9c: 00000000 .... DCD 0
0x70007aa0: 64253d6f o=%d DCD 1680162159
0x70007aa4: 00000000 .... DCD 0
0x70007aa8: 64253d70 p=%d DCD 1680162160
0x70007aac: 00000000 .... DCD 0
0x70007ab0: 64253d71 q=%d DCD 1680162161
0x70007ab4: 00000000 .... DCD 0
0x70007ab8: 64253d72 r=%d DCD 1680162162
0x70007abc: 00000000 .... DCD 0
0x70007ac0: 64253d73 s=%d DCD 1680162163
0x70007ac4: 00000000 .... DCD 0
0x70007ac8: 64253d74 t=%d DCD 1680162164
ADR produces
position-independent code, because the assembler generates an instruction that adds or subtracts a value to the PC.
C language specification: C89, C90, C95, C99
This article is reproduced
[K & R C] 1978 years, Dennis Ritchie and Brian Kernighan co-launched "The C Programming Language" of the first edition (in accordance with established practice, the classics must have referred to, the writings referred to as K & R), a reference guide in the end of the book (Reference Manual ) one gives a complete definition of the C language, to become the de factostandard for the C language was known as K & R C. This year, the C language is ported to a variety of models, and are subject to a wide range of support, the C language in the software development almost dominate the world.
C89 (ANSI C) with the C language in many areas of promotion, application, some new featurescontinue to be a variety of compiler implemented and added. Thus, the establishment of a new "unambiguous, specific platform-independent C language definition become more and more important things. In 1983, ASC X3 (ANSI under responsible for information technologystandards of the institution, now renamed as INCITS) set up a dedicated Technical Committee J11 (J11 Commission, Stands for X3J11), responsible for drafting the draftstandard on the C language. 1989, the draft ANSI formally adopted the American NationalStandards, known as the C89 standard.
C90 (ISO C)? followed the "The C Programming Language" second edition was published, the book contents updated according to the ANSI C (C89). In 1990, the ISO / IEC JTC1/SC22/WG14 (ISO / IEC Joint Technical Commission I 22 Sub-Committee 14 Working Group) efforts, ISO approved ANSI C as an international standard. So the ISO C (also known as C90) was born. In addition to some of the details of the standard document printing arrangement ISO C (C90) and ANSI C (C89) is technically exactly the same.
[C95], ISO 1994, 1996 were published C90 errata document, correct some typographical errors, and in 1995 passed a C90 Technical Supplement C90 slight expansion after expansion ISO C is called C95.
[C99] 1999, ANSI and ISO passed the latest version of the C language standards and technical errata document, thestandard is known as C99. This is basically on the C language, the most authoritative definition.
, C compiler provides full support of C89 (C90) C99 provides only partial support, there are still some support for some K & R C style.
The C language specification C89 (c90), C95 (94) and c99. C89 is a the earliest C languagespecification, 89, 90, introduced first by the American National Standards Institute ANSI version, and later was accepted as ISO international standard (ISO / IEC 9899:1990), and thus sometimes known as C90. 94 and 96, respectively c90 two bug fixes, gcc support is a revised version of the c89 (90) C language specification. 90 Specification Version amendment in 1995, called C95 or AMD1. GCC also supports C95 specifications. The latest C specification (ISO / IEC 9899:1999), often called the C99 specification amendments enacted in 1999. C99 2001 C99error correction, gcc supports the revised specification, but so far, gcc also did not complete the full support of the C99 specification.Attached: C language origin
The first prototype of origin] C language is Algol 60 1963, Cambridge University developed it into a CPL (Combined Programing Language). In 1967, the University of Cambridge Matin Richards simplified CPL language BCPL language. In 1970, Ken Thompson of Bell Laboratories (Bell Labs) will BCPL modify, and named their B language means to extract the essence of the CPL (the Boiling CPL down to its basic good features). And wrote the first UNIX system B language. In 1973, AT & T Bell Labs, Dennis Ritchie (DMRitchie) on the basis of language BCPL and B to design a new language, take the second letter in the name of BCPL, which is the famous C language. Shortly thereafter, the UNIX kernel (Kernel) and applications entirely in C rewritten Since then, C language has become the most widely used UNIX environment mainstream programming languages.