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28 lines
826 B
28 lines
826 B
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#include <stdint.h>
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#include "platform.h"
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#include "primitives.h"
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uint64_t softfloat_estimateDiv128To64( uint64_t a64, uint64_t a0, uint64_t b )
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{
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uint32_t b32;
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uint64_t z;
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struct uint128 term, rem;
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uint64_t rem32;
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if ( b <= a64 ) return UINT64_C( 0xFFFFFFFFFFFFFFFF );
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b32 = b>>32;
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z = ( (uint64_t) b32<<32 <= a64 ) ? UINT64_C( 0xFFFFFFFF00000000 )
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: ( a64 / b32 )<<32;
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term = softfloat_mul64To128( b, z );
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rem = softfloat_sub128( a64, a0, term.v64, term.v0 );
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while ( UINT64_C( 0x8000000000000000 ) <= rem.v64 ) {
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z -= UINT64_C( 0x100000000 );
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rem = softfloat_add128( rem.v64, rem.v0, b32, (uint64_t) ( b<<32 ) );
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}
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rem32 = ( rem.v64<<32 ) | ( rem.v0>>32 );
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z |= ( (uint64_t) b32<<32 <= rem32 ) ? 0xFFFFFFFF : rem32 / b32;
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return z;
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}
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