Ignore:
Timestamp:
Apr 3, 2012, 11:32:18 PM (8 years ago)
Author:
sam
Message:

math: remove old non-working vector code for the float to half conversion.

File:
1 edited

Legend:

Unmodified
Added
Removed
  • trunk/src/math/half.cpp

    r1186 r1188  
    112112}
    113113
    114 #if 0
    115 static inline void float_to_half_vector(half *dst, float const *src)
    116 {
    117     vector unsigned int const v7 = vec_splat_u32(7);
    118     vector unsigned short const v6 = vec_splat_u16(6);
    119 #if _XBOX
    120     vector signed short const v9 = vec_splat_u16(9);
    121     vector unsigned short const v10 = vec_splat_u16(10);
    122 #else
    123     vector signed short const v0x0040 = {
    124         0x0040, 0x0040, 0x0040, 0x0040, 0x0040, 0x0040, 0x0040, 0x0040};
    125     vector unsigned short const v0x0400 = {
    126         0x0400, 0x0400, 0x0400, 0x0400, 0x0400, 0x0400, 0x0400, 0x0400};
    127 #endif
    128     vector unsigned char const shuffle_high = {
    129         0, 1, 4, 5, 8, 9, 12, 13, 16, 17, 20, 21, 24, 25, 28, 29};
    130     vector unsigned char const shuffle_low = {
    131         2, 3, 6, 7, 10, 11, 14, 15, 18, 19, 22, 23, 26, 27, 30, 31};
    132     vector unsigned char const v0xbf70 = {
    133         0xbf, 0x70, 0xbf, 0x70, 0xbf, 0x70, 0xbf, 0x70,
    134         0xbf, 0x70, 0xbf, 0x70, 0xbf, 0x70, 0xbf, 0x70};
    135 
    136     vector unsigned short v_mant, v_ret;
    137     vector signed short v_exp;
    138     vector unsigned int in0 = (vector unsigned int)vec_ld(0, src);
    139     vector unsigned int in1 = (vector unsigned int)vec_ld(16, src);
    140 
    141     in0 = vec_sra(in0, v7);
    142     in1 = vec_sra(in1, v7);
    143     v_exp = (vector signed short)vec_perm(in0, in1, shuffle_high);
    144     v_mant = (vector unsigned short)vec_perm(in0, in1, shuffle_low);
    145     v_exp = (vector signed short)vec_subs((vector unsigned char)v_exp, v0xbf70);
    146 #if _XBOX
    147     v_ret = (vector unsigned short)vec_or(v_exp, vec_sr(v_exp, v9));
    148 #else
    149     v_ret = (vector unsigned short)vec_madds(v_exp, v0x0040, v_exp);
    150 #endif
    151     v_mant = vec_sr(v_mant, v6);
    152 #if _XBOX
    153     v_ret = vec_or(v_mant, vec_sl(v_ret, v10));
    154 #else
    155     v_ret = vec_mladd(v_ret, v0x0400, v_mant);
    156 #endif
    157     vec_st(v_ret, 0, (uint16_t *)dst);
    158 }
    159 #endif
    160 
    161114/* We use this magic table, inspired by De Bruijn sequences, to compute a
    162115 * branchless integer log2. The actual value fetched is 24-log2(x+1) for x
    163  * in 1, 3, 7, f, 1f, 3f, 7f, ff, 1fe, 1ff, 3fc, 3fd, 3fe, 3ff. */
     116 * in 1, 3, 7, f, 1f, 3f, 7f, ff, 1fe, 1ff, 3fc, 3fd, 3fe, 3ff. See
     117 * http://lol.zoy.org/blog/2012/4/3/beyond-de-bruijn for an explanation
     118 * of how the value 0x5a1a1a2u was obtained. */
    164119static int const shifttable[16] =
    165120{
    166121    23, 22, 21, 15, -1, 20, 18, 14, 14, 16, 19, -1, 17, -1, -1, -1,
    167122};
    168 static uint32_t const shiftmagic = 0x05a1a1a2u;
     123static uint32_t const shiftmagic = 0x5a1a1a2u;
    169124
    170125/* Lookup table-based algorithm from “Fast Half Float Conversions”
     
    286241        u.f = *src++;
    287242        *dst++ = makebits(float_to_half_nobranch(u.x));
    288 #if 0
    289         /* AltiVec code. Will work one day. */
    290         float_to_half_vector(dst, src);
    291         src += 8;
    292         dst += 8;
    293         i += 7;
    294 #endif
    295243    }
    296244
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