| |
| /* |
| =============================================================================== |
| |
| This C source fragment is part of the SoftFloat IEC/IEEE Floating-point |
| Arithmetic Package, Release 2. |
| |
| Written by John R. Hauser. This work was made possible in part by the |
| International Computer Science Institute, located at Suite 600, 1947 Center |
| Street, Berkeley, California 94704. Funding was partially provided by the |
| National Science Foundation under grant MIP-9311980. The original version |
| of this code was written as part of a project to build a fixed-point vector |
| processor in collaboration with the University of California at Berkeley, |
| overseen by Profs. Nelson Morgan and John Wawrzynek. More information |
| is available through the web page `http://HTTP.CS.Berkeley.EDU/~jhauser/ |
| arithmetic/softfloat.html'. |
| |
| THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE. Although reasonable effort |
| has been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT |
| TIMES RESULT IN INCORRECT BEHAVIOR. USE OF THIS SOFTWARE IS RESTRICTED TO |
| PERSONS AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ANY |
| AND ALL LOSSES, COSTS, OR OTHER PROBLEMS ARISING FROM ITS USE. |
| |
| Derivative works are acceptable, even for commercial purposes, so long as |
| (1) they include prominent notice that the work is derivative, and (2) they |
| include prominent notice akin to these three paragraphs for those parts of |
| this code that are retained. |
| |
| =============================================================================== |
| */ |
| |
| /* |
| ------------------------------------------------------------------------------- |
| Shifts `a' right by the number of bits given in `count'. If any nonzero |
| bits are shifted off, they are ``jammed'' into the least significant bit of |
| the result by setting the least significant bit to 1. The value of `count' |
| can be arbitrarily large; in particular, if `count' is greater than 32, the |
| result will be either 0 or 1, depending on whether `a' is zero or nonzero. |
| The result is stored in the location pointed to by `zPtr'. |
| ------------------------------------------------------------------------------- |
| */ |
| INLINE void shift32RightJamming( bits32 a, int16 count, bits32 *zPtr ) |
| { |
| bits32 z; |
| if ( count == 0 ) { |
| z = a; |
| } |
| else if ( count < 32 ) { |
| z = ( a>>count ) | ( ( a<<( ( - count ) & 31 ) ) != 0 ); |
| } |
| else { |
| z = ( a != 0 ); |
| } |
| *zPtr = z; |
| } |
| |
| /* |
| ------------------------------------------------------------------------------- |
| Shifts `a' right by the number of bits given in `count'. If any nonzero |
| bits are shifted off, they are ``jammed'' into the least significant bit of |
| the result by setting the least significant bit to 1. The value of `count' |
| can be arbitrarily large; in particular, if `count' is greater than 64, the |
| result will be either 0 or 1, depending on whether `a' is zero or nonzero. |
| The result is stored in the location pointed to by `zPtr'. |
| ------------------------------------------------------------------------------- |
| */ |
| INLINE void shift64RightJamming( bits64 a, int16 count, bits64 *zPtr ) |
| { |
| bits64 z; |
| |
| __asm__("@shift64RightJamming -- start"); |
| if ( count == 0 ) { |
| z = a; |
| } |
| else if ( count < 64 ) { |
| z = ( a>>count ) | ( ( a<<( ( - count ) & 63 ) ) != 0 ); |
| } |
| else { |
| z = ( a != 0 ); |
| } |
| __asm__("@shift64RightJamming -- end"); |
| *zPtr = z; |
| } |
| |
| /* |
| ------------------------------------------------------------------------------- |
| Shifts the 128-bit value formed by concatenating `a0' and `a1' right by 64 |
| _plus_ the number of bits given in `count'. The shifted result is at most |
| 64 nonzero bits; this is stored at the location pointed to by `z0Ptr'. The |
| bits shifted off form a second 64-bit result as follows: The _last_ bit |
| shifted off is the most-significant bit of the extra result, and the other |
| 63 bits of the extra result are all zero if and only if _all_but_the_last_ |
| bits shifted off were all zero. This extra result is stored in the location |
| pointed to by `z1Ptr'. The value of `count' can be arbitrarily large. |
| (This routine makes more sense if `a0' and `a1' are considered to form a |
| fixed-point value with binary point between `a0' and `a1'. This fixed-point |
| value is shifted right by the number of bits given in `count', and the |
| integer part of the result is returned at the location pointed to by |
| `z0Ptr'. The fractional part of the result may be slightly corrupted as |
| described above, and is returned at the location pointed to by `z1Ptr'.) |
| ------------------------------------------------------------------------------- |
| */ |
| INLINE void |
| shift64ExtraRightJamming( |
| bits64 a0, bits64 a1, int16 count, bits64 *z0Ptr, bits64 *z1Ptr ) |
| { |
| bits64 z0, z1; |
| int8 negCount = ( - count ) & 63; |
| |
| if ( count == 0 ) { |
| z1 = a1; |
| z0 = a0; |
| } |
| else if ( count < 64 ) { |
| z1 = ( a0<<negCount ) | ( a1 != 0 ); |
| z0 = a0>>count; |
| } |
| else { |
| if ( count == 64 ) { |
| z1 = a0 | ( a1 != 0 ); |
| } |
| else { |
| z1 = ( ( a0 | a1 ) != 0 ); |
| } |
| z0 = 0; |
| } |
| *z1Ptr = z1; |
| *z0Ptr = z0; |
| |
| } |
| |
| /* |
| ------------------------------------------------------------------------------- |
| Shifts the 128-bit value formed by concatenating `a0' and `a1' right by the |
| number of bits given in `count'. Any bits shifted off are lost. The value |
| of `count' can be arbitrarily large; in particular, if `count' is greater |
| than 128, the result will be 0. The result is broken into two 64-bit pieces |
| which are stored at the locations pointed to by `z0Ptr' and `z1Ptr'. |
| ------------------------------------------------------------------------------- |
| */ |
| INLINE void |
| shift128Right( |
| bits64 a0, bits64 a1, int16 count, bits64 *z0Ptr, bits64 *z1Ptr ) |
| { |
| bits64 z0, z1; |
| int8 negCount = ( - count ) & 63; |
| |
| if ( count == 0 ) { |
| z1 = a1; |
| z0 = a0; |
| } |
| else if ( count < 64 ) { |
| z1 = ( a0<<negCount ) | ( a1>>count ); |
| z0 = a0>>count; |
| } |
| else { |
| z1 = ( count < 64 ) ? ( a0>>( count & 63 ) ) : 0; |
| z0 = 0; |
| } |
| *z1Ptr = z1; |
| *z0Ptr = z0; |
| |
| } |
| |
| /* |
| ------------------------------------------------------------------------------- |
| Shifts the 128-bit value formed by concatenating `a0' and `a1' right by the |
| number of bits given in `count'. If any nonzero bits are shifted off, they |
| are ``jammed'' into the least significant bit of the result by setting the |
| least significant bit to 1. The value of `count' can be arbitrarily large; |
| in particular, if `count' is greater than 128, the result will be either 0 |
| or 1, depending on whether the concatenation of `a0' and `a1' is zero or |
| nonzero. The result is broken into two 64-bit pieces which are stored at |
| the locations pointed to by `z0Ptr' and `z1Ptr'. |
| ------------------------------------------------------------------------------- |
| */ |
| INLINE void |
| shift128RightJamming( |
| bits64 a0, bits64 a1, int16 count, bits64 *z0Ptr, bits64 *z1Ptr ) |
| { |
| bits64 z0, z1; |
| int8 negCount = ( - count ) & 63; |
| |
| if ( count == 0 ) { |
| z1 = a1; |
| z0 = a0; |
| } |
| else if ( count < 64 ) { |
| z1 = ( a0<<negCount ) | ( a1>>count ) | ( ( a1<<negCount ) != 0 ); |
| z0 = a0>>count; |
| } |
| else { |
| if ( count == 64 ) { |
| z1 = a0 | ( a1 != 0 ); |
| } |
| else if ( count < 128 ) { |
| z1 = ( a0>>( count & 63 ) ) | ( ( ( a0<<negCount ) | a1 ) != 0 ); |
| } |
| else { |
| z1 = ( ( a0 | a1 ) != 0 ); |
| } |
| z0 = 0; |
| } |
| *z1Ptr = z1; |
| *z0Ptr = z0; |
| |
| } |
| |
| /* |
| ------------------------------------------------------------------------------- |
| Shifts the 192-bit value formed by concatenating `a0', `a1', and `a2' right |
| by 64 _plus_ the number of bits given in `count'. The shifted result is |
| at most 128 nonzero bits; these are broken into two 64-bit pieces which are |
| stored at the locations pointed to by `z0Ptr' and `z1Ptr'. The bits shifted |
| off form a third 64-bit result as follows: The _last_ bit shifted off is |
| the most-significant bit of the extra result, and the other 63 bits of the |
| extra result are all zero if and only if _all_but_the_last_ bits shifted off |
| were all zero. This extra result is stored in the location pointed to by |
| `z2Ptr'. The value of `count' can be arbitrarily large. |
| (This routine makes more sense if `a0', `a1', and `a2' are considered |
| to form a fixed-point value with binary point between `a1' and `a2'. This |
| fixed-point value is shifted right by the number of bits given in `count', |
| and the integer part of the result is returned at the locations pointed to |
| by `z0Ptr' and `z1Ptr'. The fractional part of the result may be slightly |
| corrupted as described above, and is returned at the location pointed to by |
| `z2Ptr'.) |
| ------------------------------------------------------------------------------- |
| */ |
| INLINE void |
| shift128ExtraRightJamming( |
| bits64 a0, |
| bits64 a1, |
| bits64 a2, |
| int16 count, |
| bits64 *z0Ptr, |
| bits64 *z1Ptr, |
| bits64 *z2Ptr |
| ) |
| { |
| bits64 z0, z1, z2; |
| int8 negCount = ( - count ) & 63; |
| |
| if ( count == 0 ) { |
| z2 = a2; |
| z1 = a1; |
| z0 = a0; |
| } |
| else { |
| if ( count < 64 ) { |
| z2 = a1<<negCount; |
| z1 = ( a0<<negCount ) | ( a1>>count ); |
| z0 = a0>>count; |
| } |
| else { |
| if ( count == 64 ) { |
| z2 = a1; |
| z1 = a0; |
| } |
| else { |
| a2 |= a1; |
| if ( count < 128 ) { |
| z2 = a0<<negCount; |
| z1 = a0>>( count & 63 ); |
| } |
| else { |
| z2 = ( count == 128 ) ? a0 : ( a0 != 0 ); |
| z1 = 0; |
| } |
| } |
| z0 = 0; |
| } |
| z2 |= ( a2 != 0 ); |
| } |
| *z2Ptr = z2; |
| *z1Ptr = z1; |
| *z0Ptr = z0; |
| |
| } |
| |
| /* |
| ------------------------------------------------------------------------------- |
| Shifts the 128-bit value formed by concatenating `a0' and `a1' left by the |
| number of bits given in `count'. Any bits shifted off are lost. The value |
| of `count' must be less than 64. The result is broken into two 64-bit |
| pieces which are stored at the locations pointed to by `z0Ptr' and `z1Ptr'. |
| ------------------------------------------------------------------------------- |
| */ |
| INLINE void |
| shortShift128Left( |
| bits64 a0, bits64 a1, int16 count, bits64 *z0Ptr, bits64 *z1Ptr ) |
| { |
| |
| *z1Ptr = a1<<count; |
| *z0Ptr = |
| ( count == 0 ) ? a0 : ( a0<<count ) | ( a1>>( ( - count ) & 63 ) ); |
| |
| } |
| |
| /* |
| ------------------------------------------------------------------------------- |
| Shifts the 192-bit value formed by concatenating `a0', `a1', and `a2' left |
| by the number of bits given in `count'. Any bits shifted off are lost. |
| The value of `count' must be less than 64. The result is broken into three |
| 64-bit pieces which are stored at the locations pointed to by `z0Ptr', |
| `z1Ptr', and `z2Ptr'. |
| ------------------------------------------------------------------------------- |
| */ |
| INLINE void |
| shortShift192Left( |
| bits64 a0, |
| bits64 a1, |
| bits64 a2, |
| int16 count, |
| bits64 *z0Ptr, |
| bits64 *z1Ptr, |
| bits64 *z2Ptr |
| ) |
| { |
| bits64 z0, z1, z2; |
| int8 negCount; |
| |
| z2 = a2<<count; |
| z1 = a1<<count; |
| z0 = a0<<count; |
| if ( 0 < count ) { |
| negCount = ( ( - count ) & 63 ); |
| z1 |= a2>>negCount; |
| z0 |= a1>>negCount; |
| } |
| *z2Ptr = z2; |
| *z1Ptr = z1; |
| *z0Ptr = z0; |
| |
| } |
| |
| /* |
| ------------------------------------------------------------------------------- |
| Adds the 128-bit value formed by concatenating `a0' and `a1' to the 128-bit |
| value formed by concatenating `b0' and `b1'. Addition is modulo 2^128, so |
| any carry out is lost. The result is broken into two 64-bit pieces which |
| are stored at the locations pointed to by `z0Ptr' and `z1Ptr'. |
| ------------------------------------------------------------------------------- |
| */ |
| INLINE void |
| add128( |
| bits64 a0, bits64 a1, bits64 b0, bits64 b1, bits64 *z0Ptr, bits64 *z1Ptr ) |
| { |
| bits64 z1; |
| |
| z1 = a1 + b1; |
| *z1Ptr = z1; |
| *z0Ptr = a0 + b0 + ( z1 < a1 ); |
| |
| } |
| |
| /* |
| ------------------------------------------------------------------------------- |
| Adds the 192-bit value formed by concatenating `a0', `a1', and `a2' to the |
| 192-bit value formed by concatenating `b0', `b1', and `b2'. Addition is |
| modulo 2^192, so any carry out is lost. The result is broken into three |
| 64-bit pieces which are stored at the locations pointed to by `z0Ptr', |
| `z1Ptr', and `z2Ptr'. |
| ------------------------------------------------------------------------------- |
| */ |
| INLINE void |
| add192( |
| bits64 a0, |
| bits64 a1, |
| bits64 a2, |
| bits64 b0, |
| bits64 b1, |
| bits64 b2, |
| bits64 *z0Ptr, |
| bits64 *z1Ptr, |
| bits64 *z2Ptr |
| ) |
| { |
| bits64 z0, z1, z2; |
| int8 carry0, carry1; |
| |
| z2 = a2 + b2; |
| carry1 = ( z2 < a2 ); |
| z1 = a1 + b1; |
| carry0 = ( z1 < a1 ); |
| z0 = a0 + b0; |
| z1 += carry1; |
| z0 += ( z1 < carry1 ); |
| z0 += carry0; |
| *z2Ptr = z2; |
| *z1Ptr = z1; |
| *z0Ptr = z0; |
| |
| } |
| |
| /* |
| ------------------------------------------------------------------------------- |
| Subtracts the 128-bit value formed by concatenating `b0' and `b1' from the |
| 128-bit value formed by concatenating `a0' and `a1'. Subtraction is modulo |
| 2^128, so any borrow out (carry out) is lost. The result is broken into two |
| 64-bit pieces which are stored at the locations pointed to by `z0Ptr' and |
| `z1Ptr'. |
| ------------------------------------------------------------------------------- |
| */ |
| INLINE void |
| sub128( |
| bits64 a0, bits64 a1, bits64 b0, bits64 b1, bits64 *z0Ptr, bits64 *z1Ptr ) |
| { |
| |
| *z1Ptr = a1 - b1; |
| *z0Ptr = a0 - b0 - ( a1 < b1 ); |
| |
| } |
| |
| /* |
| ------------------------------------------------------------------------------- |
| Subtracts the 192-bit value formed by concatenating `b0', `b1', and `b2' |
| from the 192-bit value formed by concatenating `a0', `a1', and `a2'. |
| Subtraction is modulo 2^192, so any borrow out (carry out) is lost. The |
| result is broken into three 64-bit pieces which are stored at the locations |
| pointed to by `z0Ptr', `z1Ptr', and `z2Ptr'. |
| ------------------------------------------------------------------------------- |
| */ |
| INLINE void |
| sub192( |
| bits64 a0, |
| bits64 a1, |
| bits64 a2, |
| bits64 b0, |
| bits64 b1, |
| bits64 b2, |
| bits64 *z0Ptr, |
| bits64 *z1Ptr, |
| bits64 *z2Ptr |
| ) |
| { |
| bits64 z0, z1, z2; |
| int8 borrow0, borrow1; |
| |
| z2 = a2 - b2; |
| borrow1 = ( a2 < b2 ); |
| z1 = a1 - b1; |
| borrow0 = ( a1 < b1 ); |
| z0 = a0 - b0; |
| z0 -= ( z1 < borrow1 ); |
| z1 -= borrow1; |
| z0 -= borrow0; |
| *z2Ptr = z2; |
| *z1Ptr = z1; |
| *z0Ptr = z0; |
| |
| } |
| |
| /* |
| ------------------------------------------------------------------------------- |
| Multiplies `a' by `b' to obtain a 128-bit product. The product is broken |
| into two 64-bit pieces which are stored at the locations pointed to by |
| `z0Ptr' and `z1Ptr'. |
| ------------------------------------------------------------------------------- |
| */ |
| INLINE void mul64To128( bits64 a, bits64 b, bits64 *z0Ptr, bits64 *z1Ptr ) |
| { |
| bits32 aHigh, aLow, bHigh, bLow; |
| bits64 z0, zMiddleA, zMiddleB, z1; |
| |
| aLow = a; |
| aHigh = a>>32; |
| bLow = b; |
| bHigh = b>>32; |
| z1 = ( (bits64) aLow ) * bLow; |
| zMiddleA = ( (bits64) aLow ) * bHigh; |
| zMiddleB = ( (bits64) aHigh ) * bLow; |
| z0 = ( (bits64) aHigh ) * bHigh; |
| zMiddleA += zMiddleB; |
| z0 += ( ( (bits64) ( zMiddleA < zMiddleB ) )<<32 ) + ( zMiddleA>>32 ); |
| zMiddleA <<= 32; |
| z1 += zMiddleA; |
| z0 += ( z1 < zMiddleA ); |
| *z1Ptr = z1; |
| *z0Ptr = z0; |
| |
| } |
| |
| /* |
| ------------------------------------------------------------------------------- |
| Multiplies the 128-bit value formed by concatenating `a0' and `a1' by `b' to |
| obtain a 192-bit product. The product is broken into three 64-bit pieces |
| which are stored at the locations pointed to by `z0Ptr', `z1Ptr', and |
| `z2Ptr'. |
| ------------------------------------------------------------------------------- |
| */ |
| INLINE void |
| mul128By64To192( |
| bits64 a0, |
| bits64 a1, |
| bits64 b, |
| bits64 *z0Ptr, |
| bits64 *z1Ptr, |
| bits64 *z2Ptr |
| ) |
| { |
| bits64 z0, z1, z2, more1; |
| |
| mul64To128( a1, b, &z1, &z2 ); |
| mul64To128( a0, b, &z0, &more1 ); |
| add128( z0, more1, 0, z1, &z0, &z1 ); |
| *z2Ptr = z2; |
| *z1Ptr = z1; |
| *z0Ptr = z0; |
| |
| } |
| |
| /* |
| ------------------------------------------------------------------------------- |
| Multiplies the 128-bit value formed by concatenating `a0' and `a1' to the |
| 128-bit value formed by concatenating `b0' and `b1' to obtain a 256-bit |
| product. The product is broken into four 64-bit pieces which are stored at |
| the locations pointed to by `z0Ptr', `z1Ptr', `z2Ptr', and `z3Ptr'. |
| ------------------------------------------------------------------------------- |
| */ |
| INLINE void |
| mul128To256( |
| bits64 a0, |
| bits64 a1, |
| bits64 b0, |
| bits64 b1, |
| bits64 *z0Ptr, |
| bits64 *z1Ptr, |
| bits64 *z2Ptr, |
| bits64 *z3Ptr |
| ) |
| { |
| bits64 z0, z1, z2, z3; |
| bits64 more1, more2; |
| |
| mul64To128( a1, b1, &z2, &z3 ); |
| mul64To128( a1, b0, &z1, &more2 ); |
| add128( z1, more2, 0, z2, &z1, &z2 ); |
| mul64To128( a0, b0, &z0, &more1 ); |
| add128( z0, more1, 0, z1, &z0, &z1 ); |
| mul64To128( a0, b1, &more1, &more2 ); |
| add128( more1, more2, 0, z2, &more1, &z2 ); |
| add128( z0, z1, 0, more1, &z0, &z1 ); |
| *z3Ptr = z3; |
| *z2Ptr = z2; |
| *z1Ptr = z1; |
| *z0Ptr = z0; |
| |
| } |
| |
| /* |
| ------------------------------------------------------------------------------- |
| Returns an approximation to the 64-bit integer quotient obtained by dividing |
| `b' into the 128-bit value formed by concatenating `a0' and `a1'. The |
| divisor `b' must be at least 2^63. If q is the exact quotient truncated |
| toward zero, the approximation returned lies between q and q + 2 inclusive. |
| If the exact quotient q is larger than 64 bits, the maximum positive 64-bit |
| unsigned integer is returned. |
| ------------------------------------------------------------------------------- |
| */ |
| static bits64 estimateDiv128To64( bits64 a0, bits64 a1, bits64 b ) |
| { |
| bits64 b0, b1; |
| bits64 rem0, rem1, term0, term1; |
| bits64 z; |
| if ( b <= a0 ) return LIT64( 0xFFFFFFFFFFFFFFFF ); |
| b0 = b>>32; /* hence b0 is 32 bits wide now */ |
| if ( b0<<32 <= a0 ) { |
| z = LIT64( 0xFFFFFFFF00000000 ); |
| } else { |
| z = a0; |
| do_div( z, b0 ); |
| z <<= 32; |
| } |
| mul64To128( b, z, &term0, &term1 ); |
| sub128( a0, a1, term0, term1, &rem0, &rem1 ); |
| while ( ( (sbits64) rem0 ) < 0 ) { |
| z -= LIT64( 0x100000000 ); |
| b1 = b<<32; |
| add128( rem0, rem1, b0, b1, &rem0, &rem1 ); |
| } |
| rem0 = ( rem0<<32 ) | ( rem1>>32 ); |
| if ( b0<<32 <= rem0 ) { |
| z |= 0xFFFFFFFF; |
| } else { |
| do_div( rem0, b0 ); |
| z |= rem0; |
| } |
| return z; |
| |
| } |
| |
| /* |
| ------------------------------------------------------------------------------- |
| Returns an approximation to the square root of the 32-bit significand given |
| by `a'. Considered as an integer, `a' must be at least 2^31. If bit 0 of |
| `aExp' (the least significant bit) is 1, the integer returned approximates |
| 2^31*sqrt(`a'/2^31), where `a' is considered an integer. If bit 0 of `aExp' |
| is 0, the integer returned approximates 2^31*sqrt(`a'/2^30). In either |
| case, the approximation returned lies strictly within +/-2 of the exact |
| value. |
| ------------------------------------------------------------------------------- |
| */ |
| static bits32 estimateSqrt32( int16 aExp, bits32 a ) |
| { |
| static const bits16 sqrtOddAdjustments[] = { |
| 0x0004, 0x0022, 0x005D, 0x00B1, 0x011D, 0x019F, 0x0236, 0x02E0, |
| 0x039C, 0x0468, 0x0545, 0x0631, 0x072B, 0x0832, 0x0946, 0x0A67 |
| }; |
| static const bits16 sqrtEvenAdjustments[] = { |
| 0x0A2D, 0x08AF, 0x075A, 0x0629, 0x051A, 0x0429, 0x0356, 0x029E, |
| 0x0200, 0x0179, 0x0109, 0x00AF, 0x0068, 0x0034, 0x0012, 0x0002 |
| }; |
| int8 index; |
| bits32 z; |
| bits64 A; |
| |
| index = ( a>>27 ) & 15; |
| if ( aExp & 1 ) { |
| z = 0x4000 + ( a>>17 ) - sqrtOddAdjustments[ index ]; |
| z = ( ( a / z )<<14 ) + ( z<<15 ); |
| a >>= 1; |
| } |
| else { |
| z = 0x8000 + ( a>>17 ) - sqrtEvenAdjustments[ index ]; |
| z = a / z + z; |
| z = ( 0x20000 <= z ) ? 0xFFFF8000 : ( z<<15 ); |
| if ( z <= a ) return (bits32) ( ( (sbits32) a )>>1 ); |
| } |
| A = ( (bits64) a )<<31; |
| do_div( A, z ); |
| return ( (bits32) A ) + ( z>>1 ); |
| |
| } |
| |
| /* |
| ------------------------------------------------------------------------------- |
| Returns the number of leading 0 bits before the most-significant 1 bit |
| of `a'. If `a' is zero, 32 is returned. |
| ------------------------------------------------------------------------------- |
| */ |
| static int8 countLeadingZeros32( bits32 a ) |
| { |
| static const int8 countLeadingZerosHigh[] = { |
| 8, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, |
| 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, |
| 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, |
| 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 |
| }; |
| int8 shiftCount; |
| |
| shiftCount = 0; |
| if ( a < 0x10000 ) { |
| shiftCount += 16; |
| a <<= 16; |
| } |
| if ( a < 0x1000000 ) { |
| shiftCount += 8; |
| a <<= 8; |
| } |
| shiftCount += countLeadingZerosHigh[ a>>24 ]; |
| return shiftCount; |
| |
| } |
| |
| /* |
| ------------------------------------------------------------------------------- |
| Returns the number of leading 0 bits before the most-significant 1 bit |
| of `a'. If `a' is zero, 64 is returned. |
| ------------------------------------------------------------------------------- |
| */ |
| static int8 countLeadingZeros64( bits64 a ) |
| { |
| int8 shiftCount; |
| |
| shiftCount = 0; |
| if ( a < ( (bits64) 1 )<<32 ) { |
| shiftCount += 32; |
| } |
| else { |
| a >>= 32; |
| } |
| shiftCount += countLeadingZeros32( a ); |
| return shiftCount; |
| |
| } |
| |
| /* |
| ------------------------------------------------------------------------------- |
| Returns 1 if the 128-bit value formed by concatenating `a0' and `a1' |
| is equal to the 128-bit value formed by concatenating `b0' and `b1'. |
| Otherwise, returns 0. |
| ------------------------------------------------------------------------------- |
| */ |
| INLINE flag eq128( bits64 a0, bits64 a1, bits64 b0, bits64 b1 ) |
| { |
| |
| return ( a0 == b0 ) && ( a1 == b1 ); |
| |
| } |
| |
| /* |
| ------------------------------------------------------------------------------- |
| Returns 1 if the 128-bit value formed by concatenating `a0' and `a1' is less |
| than or equal to the 128-bit value formed by concatenating `b0' and `b1'. |
| Otherwise, returns 0. |
| ------------------------------------------------------------------------------- |
| */ |
| INLINE flag le128( bits64 a0, bits64 a1, bits64 b0, bits64 b1 ) |
| { |
| |
| return ( a0 < b0 ) || ( ( a0 == b0 ) && ( a1 <= b1 ) ); |
| |
| } |
| |
| /* |
| ------------------------------------------------------------------------------- |
| Returns 1 if the 128-bit value formed by concatenating `a0' and `a1' is less |
| than the 128-bit value formed by concatenating `b0' and `b1'. Otherwise, |
| returns 0. |
| ------------------------------------------------------------------------------- |
| */ |
| INLINE flag lt128( bits64 a0, bits64 a1, bits64 b0, bits64 b1 ) |
| { |
| |
| return ( a0 < b0 ) || ( ( a0 == b0 ) && ( a1 < b1 ) ); |
| |
| } |
| |
| /* |
| ------------------------------------------------------------------------------- |
| Returns 1 if the 128-bit value formed by concatenating `a0' and `a1' is |
| not equal to the 128-bit value formed by concatenating `b0' and `b1'. |
| Otherwise, returns 0. |
| ------------------------------------------------------------------------------- |
| */ |
| INLINE flag ne128( bits64 a0, bits64 a1, bits64 b0, bits64 b1 ) |
| { |
| |
| return ( a0 != b0 ) || ( a1 != b1 ); |
| |
| } |
| |