83 lines
2.2 KiB
C
83 lines
2.2 KiB
C
/*
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* qbe_rt.c - Non-inline wrappers for QBE-compiled ƿit modules
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*
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* Provides non-inline versions of static-inline quickjs functions
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* (which QBE-generated code calls as external symbols).
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*
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* All cell_rt_* runtime functions are implemented in source/qbe_helpers.c
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* (compiled into the cell binary) and resolved via -undefined dynamic_lookup.
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*/
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#include <stdint.h>
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#include <string.h>
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#include <math.h>
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typedef uint64_t JSValue;
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typedef struct JSContext JSContext;
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#define JS_TAG_SHORT_FLOAT 5
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#define JS_TAG_NULL 7
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#define JS_VAL_NULL 7
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/* ============================================================
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Non-inline wrappers for static-inline quickjs functions
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============================================================ */
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/*
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* __JS_NewFloat64 — encode double as tagged JSValue
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* Short float: [sign:1][exp:8][mantissa:52][tag:3]
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* Returns tagged int if value is an exact integer in int32 range
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*/
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JSValue __JS_NewFloat64(JSContext *ctx, double d) {
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union { double d; uint64_t u; } u;
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u.d = d;
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uint64_t sign = u.u >> 63;
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int exp = (u.u >> 52) & 0x7FF;
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uint64_t mantissa = u.u & ((1ULL << 52) - 1);
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/* Zero */
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if (exp == 0 && mantissa == 0)
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return JS_TAG_SHORT_FLOAT;
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/* NaN/Inf → null */
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if (exp == 0x7FF)
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return JS_VAL_NULL;
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/* Subnormals → zero */
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if (exp == 0)
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return (sign << 63) | JS_TAG_SHORT_FLOAT;
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int short_exp = exp - 1023 + 127;
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if (short_exp < 1 || short_exp > 254)
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return JS_VAL_NULL;
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/* Prefer integer if exact */
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if (d >= (double)(-2147483647 - 1) && d <= (double)2147483647) {
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int32_t i = (int32_t)d;
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if ((double)i == d)
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return (uint64_t)(uint32_t)i << 1;
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}
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return (sign << 63)
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| ((uint64_t)short_exp << 55)
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| (mantissa << 3)
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| JS_TAG_SHORT_FLOAT;
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}
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/*
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* JS_IsNumber — check if value is tagged int or short float
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*/
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int JS_IsNumber(JSValue v) {
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int is_int = (v & 1) == 0;
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int is_float = (v & 7) == JS_TAG_SHORT_FLOAT;
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return is_int || is_float;
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}
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/*
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* JS_NewString — create string from C string (wraps JS_NewStringLen)
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*/
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extern JSValue JS_NewStringLen(JSContext *ctx, const char *str, size_t len);
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JSValue JS_NewString(JSContext *ctx, const char *str) {
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return JS_NewStringLen(ctx, str, strlen(str));
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}
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