From: Eric Anholt Date: Thu, 9 Sep 2010 00:49:10 +0000 (-0700) Subject: glsl: Update README talking about multi-instruction operations. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=e04f90712d8e04ce9d2fee46d0cccf818432c7d9;p=mesa.git glsl: Update README talking about multi-instruction operations. The previous thing taking multiple instructions ended up being handled at the IR level, as we suggested would be the common result. Pick a new one. --- diff --git a/src/glsl/README b/src/glsl/README index 2e501d62069..7e97b48059c 100644 --- a/src/glsl/README +++ b/src/glsl/README @@ -156,10 +156,10 @@ for the 965 fragment shader backend when that is developed. Q: How should I expand instructions that take multiple backend instructions? Sometimes you'll have to do the expansion in your code generation -- -see, for example, ir_to_mesa.cpp's handling of ir_binop_mul for -matrices. However, in many cases you'll want to do a pass over the IR -to convert non-native instructions to a series of native instructions. -For example, for the Mesa backend we have ir_div_to_mul_rcp.cpp because +see, for example, ir_to_mesa.cpp's handling of ir_unop_sqrt. However, +in many cases you'll want to do a pass over the IR to convert +non-native instructions to a series of native instructions. For +example, for the Mesa backend we have ir_div_to_mul_rcp.cpp because Mesa IR (and many hardware backends) only have a reciprocal instruction, not a divide. Implementing non-native instructions this way gives the chance for constant folding to occur, so (a / 2.0)