diff options
author | Elie Tournier <[email protected]> | 2017-08-08 19:13:45 +0100 |
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committer | Matt Turner <[email protected]> | 2019-01-09 16:42:40 -0800 |
commit | a3551ee61f8e3622b4755d6271b9bd5b40de0cb8 (patch) | |
tree | 74520ec1dd24dea36cd43fcdf9c3fce47917a3c5 /src/compiler/glsl/float64.glsl | |
parent | 4a9340154637ab6e683161108f11aa1f36d0e0c5 (diff) |
glsl: Add "built-in" functions to do fp64_to_uint(fp64)
Signed-off-by: Elie Tournier <[email protected]>
Diffstat (limited to 'src/compiler/glsl/float64.glsl')
-rw-r--r-- | src/compiler/glsl/float64.glsl | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/src/compiler/glsl/float64.glsl b/src/compiler/glsl/float64.glsl index 81d85aceeb2..f7952413fad 100644 --- a/src/compiler/glsl/float64.glsl +++ b/src/compiler/glsl/float64.glsl @@ -797,3 +797,64 @@ __fmul64(uint64_t a, uint64_t b) } return __roundAndPackFloat64(zSign, zExp, zFrac0, zFrac1, zFrac2); } + +/* Shifts the 64-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 64, the result will be 0. The result is broken into two 32-bit pieces + * which are stored at the locations pointed to by `z0Ptr' and `z1Ptr'. + */ +void +__shift64Right(uint a0, uint a1, + int count, + out uint z0Ptr, + out uint z1Ptr) +{ + uint z0; + uint z1; + int negCount = (-count) & 31; + + z0 = 0u; + z0 = mix(z0, (a0 >> count), count < 32); + z0 = mix(z0, a0, count == 0); + + z1 = mix(0u, (a0 >> (count & 31)), count < 64); + z1 = mix(z1, (a0<<negCount) | (a1>>count), count < 32); + z1 = mix(z1, a0, count == 0); + + z1Ptr = z1; + z0Ptr = z0; +} + +/* Returns the result of converting the double-precision floating-point value + * `a' to the unsigned integer format. The conversion is performed according + * to the IEEE Standard for Floating-Point Arithmetic. + */ +uint +__fp64_to_uint(uint64_t a) +{ + uint aFracLo = __extractFloat64FracLo(a); + uint aFracHi = __extractFloat64FracHi(a); + int aExp = __extractFloat64Exp(a); + uint aSign = __extractFloat64Sign(a); + + if ((aExp == 0x7FF) && ((aFracHi | aFracLo) != 0u)) + return 0xFFFFFFFFu; + + aFracHi |= mix(0u, 0x00100000u, aExp != 0); + + int shiftDist = 0x427 - aExp; + if (0 < shiftDist) + __shift64RightJamming(aFracHi, aFracLo, shiftDist, aFracHi, aFracLo); + + if ((aFracHi & 0xFFFFF000u) != 0u) + return mix(~0u, 0u, (aSign != 0u)); + + uint z = 0u; + uint zero = 0u; + __shift64Right(aFracHi, aFracLo, 12, zero, z); + + uint expt = mix(~0u, 0u, (aSign != 0u)); + + return mix(z, expt, (aSign != 0u) && (z != 0u)); +} |