51 lines
1.1 KiB
C
51 lines
1.1 KiB
C
#include "config.h"
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#include <assert.h>
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#include <ccan/bitops/bitops.h>
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#include <common/fp16.h>
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fp16_t u64_to_fp16(u64 val, bool round_up)
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{
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u16 mantissa_bits, mantissa, exponent;
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if (val == 0)
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return 0;
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/* How many bits do we need to represent mantissa? */
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mantissa_bits = bitops_hs64(val) + 1;
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/* We only have 11 bits, so if we need more, we will round. */
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if (mantissa_bits > 11) {
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exponent = mantissa_bits - 11;
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mantissa = (val >> exponent);
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/* If we're losing bits here, we're rounding down */
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if (round_up && (val & ((1ULL << exponent)-1))) {
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mantissa++;
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if (mantissa == (1 << 11)) {
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mantissa >>= 1;
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exponent++;
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}
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}
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/* huge number? Make it max. */
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if (exponent >= 32) {
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exponent = 31;
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mantissa = (1 << 11)-1;
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}
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} else {
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exponent = 0;
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mantissa = val;
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}
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assert((mantissa >> 11) == 0);
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return (exponent << 11) | mantissa;
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}
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bool amount_msat_less_fp16(struct amount_msat amt, fp16_t fp)
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{
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return amt.millisatoshis < fp16_to_u64(fp); /* Raw: fp16 compare */
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}
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bool amount_msat_greater_fp16(struct amount_msat amt, fp16_t fp)
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{
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return amt.millisatoshis > fp16_to_u64(fp); /* Raw: fp16 compare */
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}
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