30 lines
741 B
C
30 lines
741 B
C
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case OP_SCLAMP: {
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/* Clamp/wrap to signed N-bit range: [-2^(N-1), 2^(N-1)-1] */
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Value v = pop_value(vm);
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int bits = inst.operand;
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uint64_t u = 0;
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if (v.type == VAL_INT) {
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u = (uint64_t)v.i;
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} else {
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u = 0;
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}
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if (bits <= 0) {
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/* treat as no-op for invalid widths */
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} else if (bits >= 64) {
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/* 64-bit signed: nothing to mask, keep as is */
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} else {
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uint64_t mask = (1ULL << bits) - 1ULL;
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u &= mask;
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uint64_t sign_bit = 1ULL << (bits - 1);
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if (u & sign_bit) {
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/* negative value in two's complement */
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u -= (1ULL << bits);
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}
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}
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push_value(vm, make_int((int64_t)u));
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free_value(v);
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break;
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}
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