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