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https://github.com/vercel-labs/scriptc.git
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Chris Tate
9482cbadcb
- Streamline typed-array conversion, copying, and filling. - Share exact integer coercion across typed storage and scalar operators. - Cover numeric boundaries, aliased buffers, and portable execution.
26 lines
1.1 KiB
C
26 lines
1.1 KiB
C
/* Internal numeric coercions shared by scalar operators and typed storage. */
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#ifndef SCR_NUMERIC_H
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#define SCR_NUMERIC_H
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#include <float.h>
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#include <stdint.h>
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#include <string.h>
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_Static_assert(sizeof(double) == sizeof(uint64_t) && DBL_MANT_DIG == 53 && DBL_MAX_EXP == 1024,
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"numeric coercions require binary64 doubles");
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/* ToUint32 truncates toward zero and keeps the low 32 bits. Reading the
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* binary64 exponent also handles non-finite values without floating modulo.
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* Subnormals have magnitude below one; exponents >= 84 have no low bits. */
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static inline uint32_t scr_numeric_to_u32(double value) {
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uint64_t bits;
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memcpy(&bits, &value, sizeof bits);
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unsigned exponent = (unsigned)((bits >> 52) & 0x7ff);
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if (exponent < 1023 || exponent >= 1023 + 84) return 0;
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unsigned shift = exponent - 1023;
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uint64_t significand = (bits & UINT64_C(0x000fffffffffffff)) | UINT64_C(0x0010000000000000);
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uint32_t integer = shift >= 52 ? (uint32_t)(significand << (shift - 52))
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: (uint32_t)(significand >> (52 - shift));
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return bits >> 63 ? UINT32_C(0) - integer : integer;
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}
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#endif
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