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 __ffssi2(si_int a); // find least significant 1 bit 49si_int __ffsdi2(di_int a); // find least significant 1 bit 50si_int __ffsti2(ti_int a); // find least significant 1 bit 51 52si_int __paritysi2(si_int a); // bit parity 53si_int __paritydi2(di_int a); // bit parity 54si_int __parityti2(ti_int a); // bit parity 55 56si_int __popcountsi2(si_int a); // bit population 57si_int __popcountdi2(di_int a); // bit population 58si_int __popcountti2(ti_int a); // bit population 59 60uint32_t __bswapsi2(uint32_t a); // a byteswapped 61uint64_t __bswapdi2(uint64_t a); // a byteswapped 62 63// Integral arithmetic 64 65di_int __negdi2 (di_int a); // -a 66ti_int __negti2 (ti_int a); // -a 67di_int __muldi3 (di_int a, di_int b); // a * b 68ti_int __multi3 (ti_int a, ti_int b); // a * b 69si_int __divsi3 (si_int a, si_int b); // a / b signed 70di_int __divdi3 (di_int a, di_int b); // a / b signed 71ti_int __divti3 (ti_int a, ti_int b); // a / b signed 72su_int __udivsi3 (su_int n, su_int d); // a / b unsigned 73du_int __udivdi3 (du_int a, du_int b); // a / b unsigned 74tu_int __udivti3 (tu_int a, tu_int b); // a / b unsigned 75si_int __modsi3 (si_int a, si_int b); // a % b signed 76di_int __moddi3 (di_int a, di_int b); // a % b signed 77ti_int __modti3 (ti_int a, ti_int b); // a % b signed 78su_int __umodsi3 (su_int a, su_int b); // a % b unsigned 79du_int __umoddi3 (du_int a, du_int b); // a % b unsigned 80tu_int __umodti3 (tu_int a, tu_int b); // a % b unsigned 81du_int __udivmoddi4(du_int a, du_int b, du_int* rem); // a / b, *rem = a % b unsigned 82tu_int __udivmodti4(tu_int a, tu_int b, tu_int* rem); // a / b, *rem = a % b unsigned 83su_int __udivmodsi4(su_int a, su_int b, su_int* rem); // a / b, *rem = a % b unsigned 84si_int __divmodsi4(si_int a, si_int b, si_int* rem); // a / b, *rem = a % b signed 85 86 87 88// Integral arithmetic with trapping overflow 89 90si_int __absvsi2(si_int a); // abs(a) 91di_int __absvdi2(di_int a); // abs(a) 92ti_int __absvti2(ti_int a); // abs(a) 93 94si_int __negvsi2(si_int a); // -a 95di_int __negvdi2(di_int a); // -a 96ti_int __negvti2(ti_int a); // -a 97 98si_int __addvsi3(si_int a, si_int b); // a + b 99di_int __addvdi3(di_int a, di_int b); // a + b 100ti_int __addvti3(ti_int a, ti_int b); // a + b 101 102si_int __subvsi3(si_int a, si_int b); // a - b 103di_int __subvdi3(di_int a, di_int b); // a - b 104ti_int __subvti3(ti_int a, ti_int b); // a - b 105 106si_int __mulvsi3(si_int a, si_int b); // a * b 107di_int __mulvdi3(di_int a, di_int b); // a * b 108ti_int __mulvti3(ti_int a, ti_int b); // a * b 109 110 111// Integral arithmetic which returns if overflow 112 113si_int __mulosi4(si_int a, si_int b, int* overflow); // a * b, overflow set to one if result not in signed range 114di_int __mulodi4(di_int a, di_int b, int* overflow); // a * b, overflow set to one if result not in signed range 115ti_int __muloti4(ti_int a, ti_int b, int* overflow); // a * b, overflow set to 116 one if result not in signed range 117 118 119// Integral comparison: a < b -> 0 120// a == b -> 1 121// a > b -> 2 122 123si_int __cmpdi2 (di_int a, di_int b); 124si_int __cmpti2 (ti_int a, ti_int b); 125si_int __ucmpdi2(du_int a, du_int b); 126si_int __ucmpti2(tu_int a, tu_int b); 127 128// Integral / floating point conversion 129 130di_int __fixsfdi( float a); 131di_int __fixdfdi( double a); 132di_int __fixxfdi(long double a); 133 134ti_int __fixsfti( float a); 135ti_int __fixdfti( double a); 136ti_int __fixxfti(long double a); 137uint64_t __fixtfdi(long double input); // ppc only, doesn't match documentation 138 139su_int __fixunssfsi( float a); 140su_int __fixunsdfsi( double a); 141su_int __fixunsxfsi(long double a); 142 143du_int __fixunssfdi( float a); 144du_int __fixunsdfdi( double a); 145du_int __fixunsxfdi(long double a); 146 147tu_int __fixunssfti( float a); 148tu_int __fixunsdfti( double a); 149tu_int __fixunsxfti(long double a); 150uint64_t __fixunstfdi(long double input); // ppc only 151 152float __floatdisf(di_int a); 153double __floatdidf(di_int a); 154long double __floatdixf(di_int a); 155long double __floatditf(int64_t a); // ppc only 156 157float __floattisf(ti_int a); 158double __floattidf(ti_int a); 159long double __floattixf(ti_int a); 160 161float __floatundisf(du_int a); 162double __floatundidf(du_int a); 163long double __floatundixf(du_int a); 164long double __floatunditf(uint64_t a); // ppc only 165 166float __floatuntisf(tu_int a); 167double __floatuntidf(tu_int a); 168long double __floatuntixf(tu_int a); 169 170// Floating point raised to integer power 171 172float __powisf2( float a, si_int b); // a ^ b 173double __powidf2( double a, si_int b); // a ^ b 174long double __powixf2(long double a, si_int b); // a ^ b 175long double __powitf2(long double a, si_int b); // ppc only, a ^ b 176 177// Complex arithmetic 178 179// (a + ib) * (c + id) 180 181 float _Complex __mulsc3( float a, float b, float c, float d); 182 double _Complex __muldc3(double a, double b, double c, double d); 183long double _Complex __mulxc3(long double a, long double b, 184 long double c, long double d); 185long double _Complex __multc3(long double a, long double b, 186 long double c, long double d); // ppc only 187 188// (a + ib) / (c + id) 189 190 float _Complex __divsc3( float a, float b, float c, float d); 191 double _Complex __divdc3(double a, double b, double c, double d); 192long double _Complex __divxc3(long double a, long double b, 193 long double c, long double d); 194long double _Complex __divtc3(long double a, long double b, 195 long double c, long double d); // ppc only 196 197 198// Runtime support 199 200// __clear_cache() is used to tell process that new instructions have been 201// written to an address range. Necessary on processors that do not have 202// a unified instruction and data cache. 203void __clear_cache(void* start, void* end); 204 205// __enable_execute_stack() is used with nested functions when a trampoline 206// function is written onto the stack and that page range needs to be made 207// executable. 208void __enable_execute_stack(void* addr); 209 210// __gcc_personality_v0() is normally only called by the system unwinder. 211// C code (as opposed to C++) normally does not need a personality function 212// because there are no catch clauses or destructors to be run. But there 213// is a C language extension __attribute__((cleanup(func))) which marks local 214// variables as needing the cleanup function "func" to be run when the 215// variable goes out of scope. That includes when an exception is thrown, 216// so a personality handler is needed. 217_Unwind_Reason_Code __gcc_personality_v0(int version, _Unwind_Action actions, 218 uint64_t exceptionClass, struct _Unwind_Exception* exceptionObject, 219 _Unwind_Context_t context); 220 221// for use with some implementations of assert() in <assert.h> 222void __eprintf(const char* format, const char* assertion_expression, 223 const char* line, const char* file); 224 225// for systems with emulated thread local storage 226void* __emutls_get_address(struct __emutls_control*); 227 228 229// Power PC specific functions 230 231// There is no C interface to the saveFP/restFP functions. They are helper 232// functions called by the prolog and epilog of functions that need to save 233// a number of non-volatile float point registers. 234saveFP 235restFP 236 237// PowerPC has a standard template for trampoline functions. This function 238// generates a custom trampoline function with the specific realFunc 239// and localsPtr values. 240void __trampoline_setup(uint32_t* trampOnStack, int trampSizeAllocated, 241 const void* realFunc, void* localsPtr); 242 243// adds two 128-bit double-double precision values ( x + y ) 244long double __gcc_qadd(long double x, long double y); 245 246// subtracts two 128-bit double-double precision values ( x - y ) 247long double __gcc_qsub(long double x, long double y); 248 249// multiples two 128-bit double-double precision values ( x * y ) 250long double __gcc_qmul(long double x, long double y); 251 252// divides two 128-bit double-double precision values ( x / y ) 253long double __gcc_qdiv(long double a, long double b); 254 255 256// ARM specific functions 257 258// There is no C interface to the switch* functions. These helper functions 259// are only needed by Thumb1 code for efficient switch table generation. 260switch16 261switch32 262switch8 263switchu8 264 265// There is no C interface to the *_vfp_d8_d15_regs functions. There are 266// called in the prolog and epilog of Thumb1 functions. When the C++ ABI use 267// SJLJ for exceptions, each function with a catch clause or destuctors needs 268// to save and restore all registers in it prolog and epliog. But there is 269// no way to access vector and high float registers from thumb1 code, so the 270// compiler must add call outs to these helper functions in the prolog and 271// epilog. 272restore_vfp_d8_d15_regs 273save_vfp_d8_d15_regs 274 275 276// Note: long ago ARM processors did not have floating point hardware support. 277// Floating point was done in software and floating point parameters were 278// passed in integer registers. When hardware support was added for floating 279// point, new *vfp functions were added to do the same operations but with 280// floating point parameters in floating point registers. 281 282// Undocumented functions 283 284float __addsf3vfp(float a, float b); // Appears to return a + b 285double __adddf3vfp(double a, double b); // Appears to return a + b 286float __divsf3vfp(float a, float b); // Appears to return a / b 287double __divdf3vfp(double a, double b); // Appears to return a / b 288int __eqsf2vfp(float a, float b); // Appears to return one 289 // iff a == b and neither is NaN. 290int __eqdf2vfp(double a, double b); // Appears to return one 291 // iff a == b and neither is NaN. 292double __extendsfdf2vfp(float a); // Appears to convert from 293 // float to double. 294int __fixdfsivfp(double a); // Appears to convert from 295 // double to int. 296int __fixsfsivfp(float a); // Appears to convert from 297 // float to int. 298unsigned int __fixunssfsivfp(float a); // Appears to convert from 299 // float to unsigned int. 300unsigned int __fixunsdfsivfp(double a); // Appears to convert from 301 // double to unsigned int. 302double __floatsidfvfp(int a); // Appears to convert from 303 // int to double. 304float __floatsisfvfp(int a); // Appears to convert from 305 // int to float. 306double __floatunssidfvfp(unsigned int a); // Appears to convert from 307 // unisgned int to double. 308float __floatunssisfvfp(unsigned int a); // Appears to convert from 309 // unisgned int to float. 310int __gedf2vfp(double a, double b); // Appears to return __gedf2 311 // (a >= b) 312int __gesf2vfp(float a, float b); // Appears to return __gesf2 313 // (a >= b) 314int __gtdf2vfp(double a, double b); // Appears to return __gtdf2 315 // (a > b) 316int __gtsf2vfp(float a, float b); // Appears to return __gtsf2 317 // (a > b) 318int __ledf2vfp(double a, double b); // Appears to return __ledf2 319 // (a <= b) 320int __lesf2vfp(float a, float b); // Appears to return __lesf2 321 // (a <= b) 322int __ltdf2vfp(double a, double b); // Appears to return __ltdf2 323 // (a < b) 324int __ltsf2vfp(float a, float b); // Appears to return __ltsf2 325 // (a < b) 326double __muldf3vfp(double a, double b); // Appears to return a * b 327float __mulsf3vfp(float a, float b); // Appears to return a * b 328int __nedf2vfp(double a, double b); // Appears to return __nedf2 329 // (a != b) 330double __negdf2vfp(double a); // Appears to return -a 331float __negsf2vfp(float a); // Appears to return -a 332float __negsf2vfp(float a); // Appears to return -a 333double __subdf3vfp(double a, double b); // Appears to return a - b 334float __subsf3vfp(float a, float b); // Appears to return a - b 335float __truncdfsf2vfp(double a); // Appears to convert from 336 // double to float. 337int __unorddf2vfp(double a, double b); // Appears to return __unorddf2 338int __unordsf2vfp(float a, float b); // Appears to return __unordsf2 339 340 341Preconditions are listed for each function at the definition when there are any. 342Any preconditions reflect the specification at 343http://gcc.gnu.org/onlinedocs/gccint/Libgcc.html#Libgcc. 344 345Assumptions are listed in "int_lib.h", and in individual files. Where possible 346assumptions are checked at compile time. 347