(('~fmax', ('fmin', a, 1.0), 0.0), ('fsat', a), '!options->lower_fsat'),
(('fsat', a), ('fmin', ('fmax', a, 0.0), 1.0), 'options->lower_fsat'),
(('fsat', ('fsat', a)), ('fsat', a)),
- (('fmin', ('fmax', ('fmin', ('fmax', a, 0.0), 1.0), 0.0), 1.0), ('fmin', ('fmax', a, 0.0), 1.0)),
+ (('fmin', ('fmax', ('fmin', ('fmax', a, b), c), b), c), ('fmin', ('fmax', a, b), c)),
+ (('imin', ('imax', ('imin', ('imax', a, b), c), b), c), ('imin', ('imax', a, b), c)),
+ (('umin', ('umax', ('umin', ('umax', a, b), c), b), c), ('umin', ('umax', a, b), c)),
+ (('extract_u8', ('imin', ('imax', a, 0), 0xff), 0), ('imin', ('imax', a, 0), 0xff)),
(('~ior', ('flt', a, b), ('flt', a, c)), ('flt', a, ('fmax', b, c))),
(('~ior', ('flt', a, c), ('flt', b, c)), ('flt', ('fmin', a, b), c)),
(('~ior', ('fge', a, b), ('fge', a, c)), ('fge', a, ('fmin', b, c))),
(('fmul', ('fneg', a), b), ('fneg', ('fmul', a, b))),
(('imul', ('ineg', a), b), ('ineg', ('imul', a, b))),
+ # Reassociate constants in add/mul chains so they can be folded together.
+ # For now, we only handle cases where the constants are separated by
+ # a single non-constant. We could do better eventually.
+ (('~fmul', '#a', ('fmul', b, '#c')), ('fmul', ('fmul', a, c), b)),
+ (('imul', '#a', ('imul', b, '#c')), ('imul', ('imul', a, c), b)),
+ (('~fadd', '#a', ('fadd', b, '#c')), ('fadd', ('fadd', a, c), b)),
+ (('iadd', '#a', ('iadd', b, '#c')), ('iadd', ('iadd', a, c), b)),
+
# Misc. lowering
(('fmod', a, b), ('fsub', a, ('fmul', b, ('ffloor', ('fdiv', a, b)))), 'options->lower_fmod'),
(('frem', a, b), ('fsub', a, ('fmul', b, ('ftrunc', ('fdiv', a, b)))), 'options->lower_fmod'),
]
def fexp2i(exp):
- # We assume that exp is already in range.
+ # We assume that exp is already in the range [-126, 127].
return ('ishl', ('iadd', exp, 127), 23)
def ldexp32(f, exp):
- # First, we clamp exp to a reasonable range. The maximum range that we
- # need is the largest range for an exponent, ([-127, 128] if you include
- # inf and 0) plus the number of mantissa bits in either direction to
- # account for denormals. This means that we need at least a range of
- # [-150, 151]. For our implementation, however, what we really care
- # about is that neither exp/2 nor exp-exp/2 go out of the regular range
- # for floating-point exponents.
+ # First, we clamp exp to a reasonable range. The maximum possible range
+ # for a normal exponent is [-126, 127] and, throwing in denormals, you get
+ # a maximum range of [-149, 127]. This means that we can potentially have
+ # a swing of +-276. If you start with FLT_MAX, you actually have to do
+ # ldexp(FLT_MAX, -278) to get it to flush all the way to zero. The GLSL
+ # spec, on the other hand, only requires that we handle an exponent value
+ # in the range [-126, 128]. This implementation is *mostly* correct; it
+ # handles a range on exp of [-252, 254] which allows you to create any
+ # value (including denorms if the hardware supports it) and to adjust the
+ # exponent of any normal value to anything you want.
exp = ('imin', ('imax', exp, -252), 254)
# Now we compute two powers of 2, one for exp/2 and one for exp-exp/2.
- # While the spec technically defines ldexp as f * 2.0^exp, simply
- # multiplying once doesn't work when denormals are involved because
- # 2.0^exp may not be representable even though ldexp(f, exp) is (see
- # comments above about range). Instead, we create two powers of two and
- # multiply by them each in turn. That way the effective range of our
- # exponent is doubled.
+ # (We use ishr which isn't the same for -1, but the -1 case still works
+ # since we use exp-exp/2 as the second exponent.) While the spec
+ # technically defines ldexp as f * 2.0^exp, simply multiplying once doesn't
+ # work with denormals and doesn't allow for the full swing in exponents
+ # that you can get with normalized values. Instead, we create two powers
+ # of two and multiply by them each in turn. That way the effective range
+ # of our exponent is doubled.
pow2_1 = fexp2i(('ishr', exp, 1))
pow2_2 = fexp2i(('isub', exp, ('ishr', exp, 1)))
return ('fmul', ('fmul', f, pow2_1), pow2_2)
projects / mesa.git / blobdiff