tgsi: clarify the semantics of DFRACEXP

[mesa.git] / src / gallium / docs / source / tgsi.rst

diff --git a/src/gallium/docs/source/tgsi.rst b/src/gallium/docs/source/tgsi.rst
index 31331ef51116cc88a322c9867669012b0e366213..fd78c40ba3cec388cd606506c040243d1f3b79be 100644 (file)
--- a/src/gallium/docs/source/tgsi.rst
+++ b/src/gallium/docs/source/tgsi.rst
@@ -1838,17 +1838,15 @@ two-component vectors with doubled precision in each component.
 
 Like the ``frexp()`` routine in many math libraries, this opcode stores the
 exponent of its source to ``dst0``, and the significand to ``dst1``, such that
-:math:`dst1 \times 2^{dst0} = src` .
+:math:`dst1 \times 2^{dst0} = src` . The results are replicated across
+channels.
 
 .. math::
 
-  dst0.xy = exp(src.xy)
+  dst0.xy = dst.zw = frac(src.xy)
 
-  dst1.xy = frac(src.xy)
+  dst1 = frac(src.xy)
 
-  dst0.zw = exp(src.zw)
-
-  dst1.zw = frac(src.zw)
 
 .. opcode:: DLDEXP - Multiply Number by Integral Power of 2
 
@@ -1859,7 +1857,7 @@ source is an integer.
 
   dst.xy = src0.xy \times 2^{src1.x}
 
-  dst.zw = src0.zw \times 2^{src1.y}
+  dst.zw = src0.zw \times 2^{src1.z}
 
 .. opcode:: DMIN - Minimum
 
@@ -3397,7 +3395,7 @@ A bit mask of ``bit index <= TGSI_SEMANTIC_SUBGROUP_INVOCATION``, i.e.
 TGSI_SEMANTIC_SUBGROUP_LT_MASK
 """"""""""""""""""""""""""""""
 
-A bit mask of ``bit index > TGSI_SEMANTIC_SUBGROUP_INVOCATION``, i.e.
+A bit mask of ``bit index < TGSI_SEMANTIC_SUBGROUP_INVOCATION``, i.e.
 ``(1 << subgroup_invocation) - 1`` in arbitrary precision arithmetic.