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| Rev | Author | Line No. | Line |
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| 6460 | siemargl | 1 | /* examples for interoperability with assembler |
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| 3 | 1. Calling assembler code from .c : see in libc\math any .asm file |
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| 4 | 2. Using inline assembler: see \include\kos32sys1.h and libc\math\fmod.c |
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| 5 | - https://gcc.gnu.org/onlinedocs/gcc-4.8.5/gcc/Extended-Asm.html |
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| 6 | - not all constraints from gcc are supported, no "f" or "t" for example |
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| 7 | - not supported clobberring st registers, must manual add "fstp %%st" at end or similar |
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| 8 | - need full suffixes for opcodes, fstpl but not fstp |
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| 9 | |||
| 10 | 3. Calling c functions from .asm: see \libc\start\start.asm:99 |
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| 11 | Remember: |
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| 12 | - small ints always passed as int32, floating point params as 64-bit |
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| 13 | - returned structs passed on stack with additional hidden 1st param |
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| 14 | - c functions can use EAX, ECX, EDX without warnings |
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| 15 | - .c default is cdecl calling convention https://en.wikipedia.org/wiki/X86_calling_conventions |
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| 16 | - dont use fastcall calling convention, tinycc realized it non-conformant way |
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| 17 | - tinycc supports only ELF object files |
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| 18 | |||
| 19 | tcc can be used as a linker |
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| 20 | */ |
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| 21 | |||
| 22 | |||
| 23 | |||
| 24 | |||
| 25 | #include |
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| 26 | #include |
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| 27 | |||
| 28 | |||
| 29 | main() |
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| 30 | { |
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| 31 | int i; |
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| 32 | for (i = 0; i < 20; i++) |
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| 33 | { |
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| 34 | printf("------------------------------------------------------\n"); |
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| 35 | printf ( "remainder of 5.3 / 2 is %f\n", remainder (5.3,2) ); |
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| 36 | printf ( "remainder of 18.5 / 4.2 is %f\n", remainder (18.5,4.2) ); |
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| 37 | //remainder of 5.3 / 2 is -0.700000 |
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| 38 | //remainder of 18.5 / 4.2 is 1.700000 |
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| 39 | |||
| 40 | printf ( "fmod of 5.3 / 2 is %f\n", fmod (5.3,2) ); |
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| 41 | printf ( "fmod of 18.5 / 4.2 is %f\n", fmod (18.5,4.2) ); |
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| 42 | // fmod of 5.3 / 2 is 1.300000 |
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| 43 | // fmod of 18.5 / 4.2 is 1.700000 |
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| 44 | |||
| 45 | double param, fractpart, intpart, result; |
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| 46 | int n; |
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| 47 | |||
| 48 | param = 3.14159265; |
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| 49 | fractpart = modf (param , &intpart); |
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| 50 | printf ("%f = %f + %f \n", param, intpart, fractpart); |
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| 51 | //3.141593 = 3.000000 + 0.141593 |
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| 52 | |||
| 53 | param = 0.95; |
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| 54 | n = 4; |
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| 55 | result = ldexp (param , n); |
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| 56 | printf ("%f * 2^%d = %f\n", param, n, result); |
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| 57 | //0.950000 * 2^4 = 15.200000 |
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| 58 | |||
| 59 | param = 8.0; |
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| 60 | result = frexp (param , &n); |
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| 61 | printf ("%f = %f * 2^%d\n", param, result, n); |
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| 62 | //8.000000 = 0.500000 * 2^4 |
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| 63 | param = 50; |
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| 64 | result = frexp (param , &n); |
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| 65 | printf ("%f = %f * 2^%d\n", param, result, n); |
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| 66 | |||
| 67 | } |
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| 68 | } |