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 81tu_int __udivmodti4(tu_int a, tu_int b, tu_int* rem); // a / b, *rem = a % b 82 83// Integral arithmetic with trapping overflow 84 85si_int __absvsi2(si_int a); // abs(a) 86di_int __absvdi2(di_int a); // abs(a) 87ti_int __absvti2(ti_int a); // abs(a) 88 89si_int __negvsi2(si_int a); // -a 90di_int __negvdi2(di_int a); // -a 91ti_int __negvti2(ti_int a); // -a 92 93si_int __addvsi3(si_int a, si_int b); // a + b 94di_int __addvdi3(di_int a, di_int b); // a + b 95ti_int __addvti3(ti_int a, ti_int b); // a + b 96 97si_int __subvsi3(si_int a, si_int b); // a - b 98di_int __subvdi3(di_int a, di_int b); // a - b 99ti_int __subvti3(ti_int a, ti_int b); // a - b 100 101si_int __mulvsi3(si_int a, si_int b); // a * b 102di_int __mulvdi3(di_int a, di_int b); // a * b 103ti_int __mulvti3(ti_int a, ti_int b); // a * b 104 105// Integral comparison: a < b -> 0 106// a == b -> 1 107// a > b -> 2 108 109si_int __cmpdi2 (di_int a, di_int b); 110si_int __cmpti2 (ti_int a, ti_int b); 111si_int __ucmpdi2(du_int a, du_int b); 112si_int __ucmpti2(tu_int a, tu_int b); 113 114// Integral / floating point conversion 115 116di_int __fixsfdi( float a); 117di_int __fixdfdi( double a); 118di_int __fixxfdi(long double a); 119 120ti_int __fixsfti( float a); 121ti_int __fixdfti( double a); 122ti_int __fixxfti(long double a); 123uint64_t __fixtfdi(long double input); // ppc only, doesn't match documentation 124 125su_int __fixunssfsi( float a); 126su_int __fixunsdfsi( double a); 127su_int __fixunsxfsi(long double a); 128 129du_int __fixunssfdi( float a); 130du_int __fixunsdfdi( double a); 131du_int __fixunsxfdi(long double a); 132 133tu_int __fixunssfti( float a); 134tu_int __fixunsdfti( double a); 135tu_int __fixunsxfti(long double a); 136uint64_t __fixunstfdi(long double input); // ppc only 137 138float __floatdisf(di_int a); 139double __floatdidf(di_int a); 140long double __floatdixf(di_int a); 141long double __floatditf(int64_t a); // ppc only 142 143float __floattisf(ti_int a); 144double __floattidf(ti_int a); 145long double __floattixf(ti_int a); 146 147float __floatundisf(du_int a); 148double __floatundidf(du_int a); 149long double __floatundixf(du_int a); 150long double __floatunditf(uint64_t a); // ppc only 151 152float __floatuntisf(tu_int a); 153double __floatuntidf(tu_int a); 154long double __floatuntixf(tu_int a); 155 156// Floating point raised to integer power 157 158float __powisf2( float a, si_int b); // a ^ b 159double __powidf2( double a, si_int b); // a ^ b 160long double __powixf2(long double a, si_int b); // a ^ b 161long double __powitf2(long double a, si_int b); // ppc only, a ^ b 162 163// Complex arithmetic 164 165// (a + ib) * (c + id) 166 167 float _Complex __mulsc3( float a, float b, float c, float d); 168 double _Complex __muldc3(double a, double b, double c, double d); 169long double _Complex __mulxc3(long double a, long double b, 170 long double c, long double d); 171long double _Complex __multc3(long double a, long double b, 172 long double c, long double d); // ppc only 173 174// (a + ib) / (c + id) 175 176 float _Complex __divsc3( float a, float b, float c, float d); 177 double _Complex __divdc3(double a, double b, double c, double d); 178long double _Complex __divxc3(long double a, long double b, 179 long double c, long double d); 180long double _Complex __divtc3(long double a, long double b, 181 long double c, long double d); // ppc only 182 183 184// Runtime support 185 186// __clear_cache() is used to tell process that new instructions have been 187// written to an address range. Necessary on processors that do not have 188// a unified instuction and data cache. 189void __clear_cache(void* start, void* end); 190 191// __enable_execute_stack() is used with nested functions when a trampoline 192// function is written onto the stack and that page range needs to be made 193// executable. 194void __enable_execute_stack(void* addr); 195 196// __gcc_personality_v0() is normally only called by the system unwinder. 197// C code (as opposed to C++) normally does not need a personality function 198// because there are no catch clauses or destructors to be run. But there 199// is a C language extension __attribute__((cleanup(func))) which marks local 200// variables as needing the cleanup function "func" to be run when the 201// variable goes out of scope. That includes when an exception is thrown, 202// so a personality handler is needed. 203_Unwind_Reason_Code __gcc_personality_v0(int version, _Unwind_Action actions, 204 uint64_t exceptionClass, struct _Unwind_Exception* exceptionObject, 205 _Unwind_Context_t context); 206 207// for use with some implementations of assert() in <assert.h> 208void __eprintf(const char* format, const char* assertion_expression, 209 const char* line, const char* file); 210 211 212 213// Power PC specific functions 214 215// There is no C interface to the saveFP/restFP functions. They are helper 216// functions called by the prolog and epilog of functions that need to save 217// a number of non-volatile float point registers. 218saveFP 219restFP 220 221// PowerPC has a standard template for trampoline functions. This function 222// generates a custom trampoline function with the specific realFunc 223// and localsPtr values. 224void __trampoline_setup(uint32_t* trampOnStack, int trampSizeAllocated, 225 const void* realFunc, void* localsPtr); 226 227// adds two 128-bit double-double precision values ( x + y ) 228long double __gcc_qadd(long double x, long double y); 229 230// subtracts two 128-bit double-double precision values ( x - y ) 231long double __gcc_qsub(long double x, long double y); 232 233// multiples two 128-bit double-double precision values ( x * y ) 234long double __gcc_qmul(long double x, long double y); 235 236// divides two 128-bit double-double precision values ( x / y ) 237long double __gcc_qdiv(long double a, long double b); 238 239 240// ARM specific functions 241 242// There is no C interface to the switch* functions. These helper functions 243// are only needed by Thumb1 code for efficient switch table generation. 244switch16 245switch32 246switch8 247switchu8 248 249// There is no C interface to the *_vfp_d8_d15_regs functions. There are 250// called in the prolog and epilog of Thumb1 functions. When the C++ ABI use 251// SJLJ for exceptions, each function with a catch clause or destuctors needs 252// to save and restore all registers in it prolog and epliog. But there is 253// no way to access vector and high float registers from thumb1 code, so the 254// compiler must add call outs to these helper functions in the prolog and 255// epilog. 256restore_vfp_d8_d15_regs 257save_vfp_d8_d15_regs 258 259 260// Note: long ago ARM processors did not have floating point hardware support. 261// Floating point was done in software and floating point parameters were 262// passed in integer registers. When hardware support was added for floating 263// point, new *vfp functions were added to do the same operations but with 264// floating point parameters in floating point registers. 265 266 267// Undocumented functions 268 269float __addsf3vfp(float a, float b); // Appears to return a + b 270double __adddf3vfp(double a, double b); // Appears to return a + b 271float __divsf3vfp(float a, float b); // Appears to return a / b 272double __divdf3vfp(double a, double b); // Appears to return a / b 273int __eqsf2vfp(float a, float b); // Appears to return one 274 // iff a == b and neither is NaN. 275int __eqdf2vfp(double a, double b); // Appears to return one 276 // iff a == b and neither is NaN. 277double __extendsfdf2vfp(float a); // Appears to convert from 278 // float to double. 279int __fixdfsivfp(double a); // Appears to convert from 280 // double to int. 281int __fixsfsivfp(float a); // Appears to convert from 282 // float to int. 283unsigned int __fixunssfsivfp(float a); // Appears to convert from 284 // float to unsigned int. 285unsigned int __fixunsdfsivfp(double a); // Appears to convert from 286 // double to unsigned int. 287double __floatsidfvfp(int a); // Appears to convert from 288 // int to double. 289float __floatsisfvfp(int a); // Appears to convert from 290 // int to float. 291double __floatunssidfvfp(unsigned int a); // Appears to convert from 292 // unisgned int to double. 293float __floatunssisfvfp(unsigned int a); // Appears to convert from 294 // unisgned int to float. 295int __gedf2vfp(double a, double b); // Appears to return __gedf2 296 // (a >= b) 297int __gesf2vfp(float a, float b); // Appears to return __gesf2 298 // (a >= b) 299int __gtdf2vfp(double a, double b); // Appears to return __gtdf2 300 // (a > b) 301int __gtsf2vfp(float a, float b); // Appears to return __gtsf2 302 // (a > b) 303int __ledf2vfp(double a, double b); // Appears to return __ledf2 304 // (a <= b) 305int __lesf2vfp(float a, float b); // Appears to return __lesf2 306 // (a <= b) 307int __ltdf2vfp(double a, double b); // Appears to return __ltdf2 308 // (a < b) 309int __ltsf2vfp(float a, float b); // Appears to return __ltsf2 310 // (a < b) 311double __muldf3vfp(double a, double b); // Appears to return a * b 312float __mulsf3vfp(float a, float b); // Appears to return a * b 313int __nedf2vfp(double a, double b); // Appears to return __nedf2 314 // (a != b) 315double __negdf2vfp(double a); // Appears to return -a 316float __negsf2vfp(float a); // Appears to return -a 317float __negsf2vfp(float a); // Appears to return -a 318double __subdf3vfp(double a, double b); // Appears to return a - b 319float __subsf3vfp(float a, float b); // Appears to return a - b 320float __truncdfsf2vfp(double a); // Appears to convert from 321 // double to float. 322int __unorddf2vfp(double a, double b); // Appears to return __unorddf2 323int __unordsf2vfp(float a, float b); // Appears to return __unordsf2 324 325 326Preconditions are listed for each function at the definition when there are any. 327Any preconditions reflect the specification at 328http://gcc.gnu.org/onlinedocs/gccint/Libgcc.html#Libgcc. 329 330Assumptions are listed in "int_lib.h", and in individual files. Where possible 331assumptions are checked at compile time. 332