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 23Please note that the libgcc specification explicitly mentions actual types of 24arguments and returned values being expressed with machine modes. 25In some cases particular types such as "int", "unsigned", "long long", etc. 26may be specified just as examples there. 27 28Here is a synopsis of the contents of this library: 29 30typedef int32_t si_int; 31typedef uint32_t su_int; 32 33typedef int64_t di_int; 34typedef uint64_t du_int; 35 36// Integral bit manipulation 37 38di_int __ashldi3(di_int a, si_int b); // a << b 39ti_int __ashlti3(ti_int a, si_int b); // a << b 40 41di_int __ashrdi3(di_int a, si_int b); // a >> b arithmetic (sign fill) 42ti_int __ashrti3(ti_int a, si_int b); // a >> b arithmetic (sign fill) 43di_int __lshrdi3(di_int a, si_int b); // a >> b logical (zero fill) 44ti_int __lshrti3(ti_int a, si_int b); // a >> b logical (zero fill) 45 46int __clzsi2(si_int a); // count leading zeros 47int __clzdi2(di_int a); // count leading zeros 48int __clzti2(ti_int a); // count leading zeros 49int __ctzsi2(si_int a); // count trailing zeros 50int __ctzdi2(di_int a); // count trailing zeros 51int __ctzti2(ti_int a); // count trailing zeros 52 53int __ffssi2(si_int a); // find least significant 1 bit 54int __ffsdi2(di_int a); // find least significant 1 bit 55int __ffsti2(ti_int a); // find least significant 1 bit 56 57int __paritysi2(si_int a); // bit parity 58int __paritydi2(di_int a); // bit parity 59int __parityti2(ti_int a); // bit parity 60 61int __popcountsi2(si_int a); // bit population 62int __popcountdi2(di_int a); // bit population 63int __popcountti2(ti_int a); // bit population 64 65uint32_t __bswapsi2(uint32_t a); // a byteswapped 66uint64_t __bswapdi2(uint64_t a); // a byteswapped 67 68// Integral arithmetic 69 70di_int __negdi2 (di_int a); // -a 71ti_int __negti2 (ti_int a); // -a 72di_int __muldi3 (di_int a, di_int b); // a * b 73ti_int __multi3 (ti_int a, ti_int b); // a * b 74si_int __divsi3 (si_int a, si_int b); // a / b signed 75di_int __divdi3 (di_int a, di_int b); // a / b signed 76ti_int __divti3 (ti_int a, ti_int b); // a / b signed 77su_int __udivsi3 (su_int n, su_int d); // a / b unsigned 78du_int __udivdi3 (du_int a, du_int b); // a / b unsigned 79tu_int __udivti3 (tu_int a, tu_int b); // a / b unsigned 80si_int __modsi3 (si_int a, si_int b); // a % b signed 81di_int __moddi3 (di_int a, di_int b); // a % b signed 82ti_int __modti3 (ti_int a, ti_int b); // a % b signed 83su_int __umodsi3 (su_int a, su_int b); // a % b unsigned 84du_int __umoddi3 (du_int a, du_int b); // a % b unsigned 85tu_int __umodti3 (tu_int a, tu_int b); // a % b unsigned 86du_int __udivmoddi4(du_int a, du_int b, du_int* rem); // a / b, *rem = a % b unsigned 87tu_int __udivmodti4(tu_int a, tu_int b, tu_int* rem); // a / b, *rem = a % b unsigned 88su_int __udivmodsi4(su_int a, su_int b, su_int* rem); // a / b, *rem = a % b unsigned 89si_int __divmodsi4(si_int a, si_int b, si_int* rem); // a / b, *rem = a % b signed 90di_int __divmoddi4(di_int a, di_int b, di_int* rem); // a / b, *rem = a % b signed 91ti_int __divmodti4(ti_int a, ti_int b, ti_int* rem); // a / b, *rem = a % b signed 92 93 94 95// Integral arithmetic with trapping overflow 96 97si_int __absvsi2(si_int a); // abs(a) 98di_int __absvdi2(di_int a); // abs(a) 99ti_int __absvti2(ti_int a); // abs(a) 100 101si_int __negvsi2(si_int a); // -a 102di_int __negvdi2(di_int a); // -a 103ti_int __negvti2(ti_int a); // -a 104 105si_int __addvsi3(si_int a, si_int b); // a + b 106di_int __addvdi3(di_int a, di_int b); // a + b 107ti_int __addvti3(ti_int a, ti_int b); // a + b 108 109si_int __subvsi3(si_int a, si_int b); // a - b 110di_int __subvdi3(di_int a, di_int b); // a - b 111ti_int __subvti3(ti_int a, ti_int b); // a - b 112 113si_int __mulvsi3(si_int a, si_int b); // a * b 114di_int __mulvdi3(di_int a, di_int b); // a * b 115ti_int __mulvti3(ti_int a, ti_int b); // a * b 116 117 118// Integral arithmetic which returns if overflow 119 120si_int __mulosi4(si_int a, si_int b, int* overflow); // a * b, overflow set to one if result not in signed range 121di_int __mulodi4(di_int a, di_int b, int* overflow); // a * b, overflow set to one if result not in signed range 122ti_int __muloti4(ti_int a, ti_int b, int* overflow); // a * b, overflow set to 123 one if result not in signed range 124 125 126// Integral comparison: a < b -> 0 127// a == b -> 1 128// a > b -> 2 129 130si_int __cmpdi2 (di_int a, di_int b); 131si_int __cmpti2 (ti_int a, ti_int b); 132si_int __ucmpdi2(du_int a, du_int b); 133si_int __ucmpti2(tu_int a, tu_int b); 134 135// Integral / floating point conversion 136 137di_int __fixsfdi( float a); 138di_int __fixdfdi( double a); 139di_int __fixxfdi(long double a); 140 141ti_int __fixsfti( float a); 142ti_int __fixdfti( double a); 143ti_int __fixxfti(long double a); 144uint64_t __fixtfdi(long double input); // ppc only, doesn't match documentation 145 146su_int __fixunssfsi( float a); 147su_int __fixunsdfsi( double a); 148su_int __fixunsxfsi(long double a); 149 150du_int __fixunssfdi( float a); 151du_int __fixunsdfdi( double a); 152du_int __fixunsxfdi(long double a); 153 154tu_int __fixunssfti( float a); 155tu_int __fixunsdfti( double a); 156tu_int __fixunsxfti(long double a); 157uint64_t __fixunstfdi(long double input); // ppc only 158 159float __floatdisf(di_int a); 160double __floatdidf(di_int a); 161long double __floatdixf(di_int a); 162long double __floatditf(int64_t a); // ppc only 163 164float __floattisf(ti_int a); 165double __floattidf(ti_int a); 166long double __floattixf(ti_int a); 167 168float __floatundisf(du_int a); 169double __floatundidf(du_int a); 170long double __floatundixf(du_int a); 171long double __floatunditf(uint64_t a); // ppc only 172 173float __floatuntisf(tu_int a); 174double __floatuntidf(tu_int a); 175long double __floatuntixf(tu_int a); 176 177// Floating point raised to integer power 178 179float __powisf2( float a, int b); // a ^ b 180double __powidf2( double a, int b); // a ^ b 181long double __powixf2(long double a, int b); // a ^ b 182long double __powitf2(long double a, int b); // ppc only, a ^ b 183 184// Complex arithmetic 185 186// (a + ib) * (c + id) 187 188 float _Complex __mulsc3( float a, float b, float c, float d); 189 double _Complex __muldc3(double a, double b, double c, double d); 190long double _Complex __mulxc3(long double a, long double b, 191 long double c, long double d); 192long double _Complex __multc3(long double a, long double b, 193 long double c, long double d); // ppc only 194 195// (a + ib) / (c + id) 196 197 float _Complex __divsc3( float a, float b, float c, float d); 198 double _Complex __divdc3(double a, double b, double c, double d); 199long double _Complex __divxc3(long double a, long double b, 200 long double c, long double d); 201long double _Complex __divtc3(long double a, long double b, 202 long double c, long double d); // ppc only 203 204 205// Runtime support 206 207// __clear_cache() is used to tell process that new instructions have been 208// written to an address range. Necessary on processors that do not have 209// a unified instruction and data cache. 210void __clear_cache(void* start, void* end); 211 212// __enable_execute_stack() is used with nested functions when a trampoline 213// function is written onto the stack and that page range needs to be made 214// executable. 215void __enable_execute_stack(void* addr); 216 217// __gcc_personality_v0() is normally only called by the system unwinder. 218// C code (as opposed to C++) normally does not need a personality function 219// because there are no catch clauses or destructors to be run. But there 220// is a C language extension __attribute__((cleanup(func))) which marks local 221// variables as needing the cleanup function "func" to be run when the 222// variable goes out of scope. That includes when an exception is thrown, 223// so a personality handler is needed. 224_Unwind_Reason_Code __gcc_personality_v0(int version, _Unwind_Action actions, 225 uint64_t exceptionClass, struct _Unwind_Exception* exceptionObject, 226 _Unwind_Context_t context); 227 228// for use with some implementations of assert() in <assert.h> 229void __eprintf(const char* format, const char* assertion_expression, 230 const char* line, const char* file); 231 232// for systems with emulated thread local storage 233void* __emutls_get_address(struct __emutls_control*); 234 235 236// Power PC specific functions 237 238// There is no C interface to the saveFP/restFP functions. They are helper 239// functions called by the prolog and epilog of functions that need to save 240// a number of non-volatile float point registers. 241saveFP 242restFP 243 244// PowerPC has a standard template for trampoline functions. This function 245// generates a custom trampoline function with the specific realFunc 246// and localsPtr values. 247void __trampoline_setup(uint32_t* trampOnStack, int trampSizeAllocated, 248 const void* realFunc, void* localsPtr); 249 250// adds two 128-bit double-double precision values ( x + y ) 251long double __gcc_qadd(long double x, long double y); 252 253// subtracts two 128-bit double-double precision values ( x - y ) 254long double __gcc_qsub(long double x, long double y); 255 256// multiples two 128-bit double-double precision values ( x * y ) 257long double __gcc_qmul(long double x, long double y); 258 259// divides two 128-bit double-double precision values ( x / y ) 260long double __gcc_qdiv(long double a, long double b); 261 262 263// ARM specific functions 264 265// There is no C interface to the switch* functions. These helper functions 266// are only needed by Thumb1 code for efficient switch table generation. 267switch16 268switch32 269switch8 270switchu8 271 272// There is no C interface to the *_vfp_d8_d15_regs functions. There are 273// called in the prolog and epilog of Thumb1 functions. When the C++ ABI use 274// SJLJ for exceptions, each function with a catch clause or destuctors needs 275// to save and restore all registers in it prolog and epliog. But there is 276// no way to access vector and high float registers from thumb1 code, so the 277// compiler must add call outs to these helper functions in the prolog and 278// epilog. 279restore_vfp_d8_d15_regs 280save_vfp_d8_d15_regs 281 282 283// Note: long ago ARM processors did not have floating point hardware support. 284// Floating point was done in software and floating point parameters were 285// passed in integer registers. When hardware support was added for floating 286// point, new *vfp functions were added to do the same operations but with 287// floating point parameters in floating point registers. 288 289// Undocumented functions 290 291float __addsf3vfp(float a, float b); // Appears to return a + b 292double __adddf3vfp(double a, double b); // Appears to return a + b 293float __divsf3vfp(float a, float b); // Appears to return a / b 294double __divdf3vfp(double a, double b); // Appears to return a / b 295int __eqsf2vfp(float a, float b); // Appears to return one 296 // iff a == b and neither is NaN. 297int __eqdf2vfp(double a, double b); // Appears to return one 298 // iff a == b and neither is NaN. 299double __extendsfdf2vfp(float a); // Appears to convert from 300 // float to double. 301int __fixdfsivfp(double a); // Appears to convert from 302 // double to int. 303int __fixsfsivfp(float a); // Appears to convert from 304 // float to int. 305unsigned int __fixunssfsivfp(float a); // Appears to convert from 306 // float to unsigned int. 307unsigned int __fixunsdfsivfp(double a); // Appears to convert from 308 // double to unsigned int. 309double __floatsidfvfp(int a); // Appears to convert from 310 // int to double. 311float __floatsisfvfp(int a); // Appears to convert from 312 // int to float. 313double __floatunssidfvfp(unsigned int a); // Appears to convert from 314 // unisgned int to double. 315float __floatunssisfvfp(unsigned int a); // Appears to convert from 316 // unisgned int to float. 317int __gedf2vfp(double a, double b); // Appears to return __gedf2 318 // (a >= b) 319int __gesf2vfp(float a, float b); // Appears to return __gesf2 320 // (a >= b) 321int __gtdf2vfp(double a, double b); // Appears to return __gtdf2 322 // (a > b) 323int __gtsf2vfp(float a, float b); // Appears to return __gtsf2 324 // (a > b) 325int __ledf2vfp(double a, double b); // Appears to return __ledf2 326 // (a <= b) 327int __lesf2vfp(float a, float b); // Appears to return __lesf2 328 // (a <= b) 329int __ltdf2vfp(double a, double b); // Appears to return __ltdf2 330 // (a < b) 331int __ltsf2vfp(float a, float b); // Appears to return __ltsf2 332 // (a < b) 333double __muldf3vfp(double a, double b); // Appears to return a * b 334float __mulsf3vfp(float a, float b); // Appears to return a * b 335int __nedf2vfp(double a, double b); // Appears to return __nedf2 336 // (a != b) 337double __negdf2vfp(double a); // Appears to return -a 338float __negsf2vfp(float a); // Appears to return -a 339float __negsf2vfp(float a); // Appears to return -a 340double __subdf3vfp(double a, double b); // Appears to return a - b 341float __subsf3vfp(float a, float b); // Appears to return a - b 342float __truncdfsf2vfp(double a); // Appears to convert from 343 // double to float. 344int __unorddf2vfp(double a, double b); // Appears to return __unorddf2 345int __unordsf2vfp(float a, float b); // Appears to return __unordsf2 346 347 348Preconditions are listed for each function at the definition when there are any. 349Any preconditions reflect the specification at 350http://gcc.gnu.org/onlinedocs/gccint/Libgcc.html#Libgcc. 351 352Assumptions are listed in "int_lib.h", and in individual files. Where possible 353assumptions are checked at compile time. 354