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22 lines
760 B
C
22 lines
760 B
C
/* See the "Run-time ABI for the ARM Architecture", Section 4.2 */
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#include <assert.h>
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typedef unsigned int uint32_t;
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long long __aeabi_llsl(long long value, int shift) {
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uint32_t low = (uint32_t)value << shift;
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/* "Shift behavior is undefined if the right operand is negative, or greater
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* than or equal to the length in bits of the promoted left operand" according
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* to C++ spec. However, arm compiler fill the vacated bits with 0 */
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assert(shift < 32 || low == 0);
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uint32_t high = ((uint32_t)(value >> 32) << shift);
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// Same comment
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assert(shift < 32 || high == 0);
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if (shift < 32) {
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high |= ((uint32_t)value >> (32 - shift));
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} else {
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high |= ((uint32_t)value << (shift - 32));
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}
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return ((long long)high << 32) | low;
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}
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