README.txt revision 222656
1Compiler-RT 2================================ 3 4This directory and its subdirectories contain source code for the compiler 5support routines. 6 7Compiler-RT is open source software. You may freely distribute it under the 8terms of the license agreement found in LICENSE.txt. 9 10================================ 11 12This is a replacement library for libgcc. Each function is contained 13in its own file. Each function has a corresponding unit test under 14test/Unit. 15 16A rudimentary script to test each file is in the file called 17test/Unit/test. 18 19Here is the specification for this library: 20 21http://gcc.gnu.org/onlinedocs/gccint/Libgcc.html#Libgcc 22 23Here is a synopsis of the contents of this library: 24 25typedef int si_int; 26typedef unsigned su_int; 27 28typedef long long di_int; 29typedef unsigned long long du_int; 30 31// Integral bit manipulation 32 33di_int __ashldi3(di_int a, si_int b); // a << b 34ti_int __ashlti3(ti_int a, si_int b); // a << b 35 36di_int __ashrdi3(di_int a, si_int b); // a >> b arithmetic (sign fill) 37ti_int __ashrti3(ti_int a, si_int b); // a >> b arithmetic (sign fill) 38di_int __lshrdi3(di_int a, si_int b); // a >> b logical (zero fill) 39ti_int __lshrti3(ti_int a, si_int b); // a >> b logical (zero fill) 40 41si_int __clzsi2(si_int a); // count leading zeros 42si_int __clzdi2(di_int a); // count leading zeros 43si_int __clzti2(ti_int a); // count leading zeros 44si_int __ctzsi2(si_int a); // count trailing zeros 45si_int __ctzdi2(di_int a); // count trailing zeros 46si_int __ctzti2(ti_int a); // count trailing zeros 47 48si_int __ffsdi2(di_int a); // find least significant 1 bit 49si_int __ffsti2(ti_int a); // find least significant 1 bit 50 51si_int __paritysi2(si_int a); // bit parity 52si_int __paritydi2(di_int a); // bit parity 53si_int __parityti2(ti_int a); // bit parity 54 55si_int __popcountsi2(si_int a); // bit population 56si_int __popcountdi2(di_int a); // bit population 57si_int __popcountti2(ti_int a); // bit population 58 59uint32_t __bswapsi2(uint32_t a); // a byteswapped, arm only 60uint64_t __bswapdi2(uint64_t a); // a byteswapped, arm only 61 62// Integral arithmetic 63 64di_int __negdi2 (di_int a); // -a 65ti_int __negti2 (ti_int a); // -a 66di_int __muldi3 (di_int a, di_int b); // a * b 67ti_int __multi3 (ti_int a, ti_int b); // a * b 68si_int __divsi3 (si_int a, si_int b); // a / b signed 69di_int __divdi3 (di_int a, di_int b); // a / b signed 70ti_int __divti3 (ti_int a, ti_int b); // a / b signed 71su_int __udivsi3 (su_int n, su_int d); // a / b unsigned 72du_int __udivdi3 (du_int a, du_int b); // a / b unsigned 73tu_int __udivti3 (tu_int a, tu_int b); // a / b unsigned 74si_int __modsi3 (si_int a, si_int b); // a % b signed 75di_int __moddi3 (di_int a, di_int b); // a % b signed 76ti_int __modti3 (ti_int a, ti_int b); // a % b signed 77su_int __umodsi3 (su_int a, su_int b); // a % b unsigned 78du_int __umoddi3 (du_int a, du_int b); // a % b unsigned 79tu_int __umodti3 (tu_int a, tu_int b); // a % b unsigned 80du_int __udivmoddi4(du_int a, du_int b, du_int* rem); // a / b, *rem = a % b unsigned 81tu_int __udivmodti4(tu_int a, tu_int b, tu_int* rem); // a / b, *rem = a % b unsigned 82su_int __udivmodsi4(su_int a, su_int b, su_int* rem); // a / b, *rem = a % b unsigned 83si_int __divmodsi4(si_int a, si_int b, si_int* rem); // a / b, *rem = a % b signed 84 85 86 87// Integral arithmetic with trapping overflow 88 89si_int __absvsi2(si_int a); // abs(a) 90di_int __absvdi2(di_int a); // abs(a) 91ti_int __absvti2(ti_int a); // abs(a) 92 93si_int __negvsi2(si_int a); // -a 94di_int __negvdi2(di_int a); // -a 95ti_int __negvti2(ti_int a); // -a 96 97si_int __addvsi3(si_int a, si_int b); // a + b 98di_int __addvdi3(di_int a, di_int b); // a + b 99ti_int __addvti3(ti_int a, ti_int b); // a + b 100 101si_int __subvsi3(si_int a, si_int b); // a - b 102di_int __subvdi3(di_int a, di_int b); // a - b 103ti_int __subvti3(ti_int a, ti_int b); // a - b 104 105si_int __mulvsi3(si_int a, si_int b); // a * b 106di_int __mulvdi3(di_int a, di_int b); // a * b 107ti_int __mulvti3(ti_int a, ti_int b); // a * b 108 109// Integral comparison: a < b -> 0 110// a == b -> 1 111// a > b -> 2 112 113si_int __cmpdi2 (di_int a, di_int b); 114si_int __cmpti2 (ti_int a, ti_int b); 115si_int __ucmpdi2(du_int a, du_int b); 116si_int __ucmpti2(tu_int a, tu_int b); 117 118// Integral / floating point conversion 119 120di_int __fixsfdi( float a); 121di_int __fixdfdi( double a); 122di_int __fixxfdi(long double a); 123 124ti_int __fixsfti( float a); 125ti_int __fixdfti( double a); 126ti_int __fixxfti(long double a); 127uint64_t __fixtfdi(long double input); // ppc only, doesn't match documentation 128 129su_int __fixunssfsi( float a); 130su_int __fixunsdfsi( double a); 131su_int __fixunsxfsi(long double a); 132 133du_int __fixunssfdi( float a); 134du_int __fixunsdfdi( double a); 135du_int __fixunsxfdi(long double a); 136 137tu_int __fixunssfti( float a); 138tu_int __fixunsdfti( double a); 139tu_int __fixunsxfti(long double a); 140uint64_t __fixunstfdi(long double input); // ppc only 141 142float __floatdisf(di_int a); 143double __floatdidf(di_int a); 144long double __floatdixf(di_int a); 145long double __floatditf(int64_t a); // ppc only 146 147float __floattisf(ti_int a); 148double __floattidf(ti_int a); 149long double __floattixf(ti_int a); 150 151float __floatundisf(du_int a); 152double __floatundidf(du_int a); 153long double __floatundixf(du_int a); 154long double __floatunditf(uint64_t a); // ppc only 155 156float __floatuntisf(tu_int a); 157double __floatuntidf(tu_int a); 158long double __floatuntixf(tu_int a); 159 160// Floating point raised to integer power 161 162float __powisf2( float a, si_int b); // a ^ b 163double __powidf2( double a, si_int b); // a ^ b 164long double __powixf2(long double a, si_int b); // a ^ b 165long double __powitf2(long double a, si_int b); // ppc only, a ^ b 166 167// Complex arithmetic 168 169// (a + ib) * (c + id) 170 171 float _Complex __mulsc3( float a, float b, float c, float d); 172 double _Complex __muldc3(double a, double b, double c, double d); 173long double _Complex __mulxc3(long double a, long double b, 174 long double c, long double d); 175long double _Complex __multc3(long double a, long double b, 176 long double c, long double d); // ppc only 177 178// (a + ib) / (c + id) 179 180 float _Complex __divsc3( float a, float b, float c, float d); 181 double _Complex __divdc3(double a, double b, double c, double d); 182long double _Complex __divxc3(long double a, long double b, 183 long double c, long double d); 184long double _Complex __divtc3(long double a, long double b, 185 long double c, long double d); // ppc only 186 187 188// Runtime support 189 190// __clear_cache() is used to tell process that new instructions have been 191// written to an address range. Necessary on processors that do not have 192// a unified instuction and data cache. 193void __clear_cache(void* start, void* end); 194 195// __enable_execute_stack() is used with nested functions when a trampoline 196// function is written onto the stack and that page range needs to be made 197// executable. 198void __enable_execute_stack(void* addr); 199 200// __gcc_personality_v0() is normally only called by the system unwinder. 201// C code (as opposed to C++) normally does not need a personality function 202// because there are no catch clauses or destructors to be run. But there 203// is a C language extension __attribute__((cleanup(func))) which marks local 204// variables as needing the cleanup function "func" to be run when the 205// variable goes out of scope. That includes when an exception is thrown, 206// so a personality handler is needed. 207_Unwind_Reason_Code __gcc_personality_v0(int version, _Unwind_Action actions, 208 uint64_t exceptionClass, struct _Unwind_Exception* exceptionObject, 209 _Unwind_Context_t context); 210 211// for use with some implementations of assert() in <assert.h> 212void __eprintf(const char* format, const char* assertion_expression, 213 const char* line, const char* file); 214 215 216 217// Power PC specific functions 218 219// There is no C interface to the saveFP/restFP functions. They are helper 220// functions called by the prolog and epilog of functions that need to save 221// a number of non-volatile float point registers. 222saveFP 223restFP 224 225// PowerPC has a standard template for trampoline functions. This function 226// generates a custom trampoline function with the specific realFunc 227// and localsPtr values. 228void __trampoline_setup(uint32_t* trampOnStack, int trampSizeAllocated, 229 const void* realFunc, void* localsPtr); 230 231// adds two 128-bit double-double precision values ( x + y ) 232long double __gcc_qadd(long double x, long double y); 233 234// subtracts two 128-bit double-double precision values ( x - y ) 235long double __gcc_qsub(long double x, long double y); 236 237// multiples two 128-bit double-double precision values ( x * y ) 238long double __gcc_qmul(long double x, long double y); 239 240// divides two 128-bit double-double precision values ( x / y ) 241long double __gcc_qdiv(long double a, long double b); 242 243 244// ARM specific functions 245 246// There is no C interface to the switch* functions. These helper functions 247// are only needed by Thumb1 code for efficient switch table generation. 248switch16 249switch32 250switch8 251switchu8 252 253// There is no C interface to the *_vfp_d8_d15_regs functions. There are 254// called in the prolog and epilog of Thumb1 functions. When the C++ ABI use 255// SJLJ for exceptions, each function with a catch clause or destuctors needs 256// to save and restore all registers in it prolog and epliog. But there is 257// no way to access vector and high float registers from thumb1 code, so the 258// compiler must add call outs to these helper functions in the prolog and 259// epilog. 260restore_vfp_d8_d15_regs 261save_vfp_d8_d15_regs 262 263 264// Note: long ago ARM processors did not have floating point hardware support. 265// Floating point was done in software and floating point parameters were 266// passed in integer registers. When hardware support was added for floating 267// point, new *vfp functions were added to do the same operations but with 268// floating point parameters in floating point registers. 269 270// Undocumented functions 271 272float __addsf3vfp(float a, float b); // Appears to return a + b 273double __adddf3vfp(double a, double b); // Appears to return a + b 274float __divsf3vfp(float a, float b); // Appears to return a / b 275double __divdf3vfp(double a, double b); // Appears to return a / b 276int __eqsf2vfp(float a, float b); // Appears to return one 277 // iff a == b and neither is NaN. 278int __eqdf2vfp(double a, double b); // Appears to return one 279 // iff a == b and neither is NaN. 280double __extendsfdf2vfp(float a); // Appears to convert from 281 // float to double. 282int __fixdfsivfp(double a); // Appears to convert from 283 // double to int. 284int __fixsfsivfp(float a); // Appears to convert from 285 // float to int. 286unsigned int __fixunssfsivfp(float a); // Appears to convert from 287 // float to unsigned int. 288unsigned int __fixunsdfsivfp(double a); // Appears to convert from 289 // double to unsigned int. 290double __floatsidfvfp(int a); // Appears to convert from 291 // int to double. 292float __floatsisfvfp(int a); // Appears to convert from 293 // int to float. 294double __floatunssidfvfp(unsigned int a); // Appears to convert from 295 // unisgned int to double. 296float __floatunssisfvfp(unsigned int a); // Appears to convert from 297 // unisgned int to float. 298int __gedf2vfp(double a, double b); // Appears to return __gedf2 299 // (a >= b) 300int __gesf2vfp(float a, float b); // Appears to return __gesf2 301 // (a >= b) 302int __gtdf2vfp(double a, double b); // Appears to return __gtdf2 303 // (a > b) 304int __gtsf2vfp(float a, float b); // Appears to return __gtsf2 305 // (a > b) 306int __ledf2vfp(double a, double b); // Appears to return __ledf2 307 // (a <= b) 308int __lesf2vfp(float a, float b); // Appears to return __lesf2 309 // (a <= b) 310int __ltdf2vfp(double a, double b); // Appears to return __ltdf2 311 // (a < b) 312int __ltsf2vfp(float a, float b); // Appears to return __ltsf2 313 // (a < b) 314double __muldf3vfp(double a, double b); // Appears to return a * b 315float __mulsf3vfp(float a, float b); // Appears to return a * b 316int __nedf2vfp(double a, double b); // Appears to return __nedf2 317 // (a != b) 318double __negdf2vfp(double a); // Appears to return -a 319float __negsf2vfp(float a); // Appears to return -a 320float __negsf2vfp(float a); // Appears to return -a 321double __subdf3vfp(double a, double b); // Appears to return a - b 322float __subsf3vfp(float a, float b); // Appears to return a - b 323float __truncdfsf2vfp(double a); // Appears to convert from 324 // double to float. 325int __unorddf2vfp(double a, double b); // Appears to return __unorddf2 326int __unordsf2vfp(float a, float b); // Appears to return __unordsf2 327 328 329Preconditions are listed for each function at the definition when there are any. 330Any preconditions reflect the specification at 331http://gcc.gnu.org/onlinedocs/gccint/Libgcc.html#Libgcc. 332 333Assumptions are listed in "int_lib.h", and in individual files. Where possible 334assumptions are checked at compile time. 335