diff options
| author | Matt Turner <[email protected]> | 2013-09-17 18:02:05 -0700 |
|---|---|---|
| committer | Matt Turner <[email protected]> | 2013-10-07 10:41:16 -0700 |
| commit | 6f9428eb68bb0f7592f4384455fc7aab23940d92 (patch) | |
| tree | 4c84da7111570d6bd02b07122bda7414d8273d36 | |
| parent | 6c125973f31addf903921647e8244abccb944e1a (diff) | |
glsl: Implement usubBorrow() built-in for ARB_gpu_shader5.
i965 implements this with a single (multiple destination) instruction,
SUBB. Emitting SUBB directly from usubBorrow() would be ideal, but our
optimization passes don't know how to copy with expressions with
side-effects.
Radeon has an SUBB_UINT instruction that only generates the borrow
bit. I've chosen to go this route and implement usubBorrow() by doing the
subtraction and the borrow operations separately.
Reviewed-by: Kenneth Graunke <[email protected]>
Reviewed-by: Ian Romanick <[email protected]>
| -rw-r--r-- | src/glsl/builtin_functions.cpp | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/src/glsl/builtin_functions.cpp b/src/glsl/builtin_functions.cpp index 9465ee3e785..5b1b9c3b7c1 100644 --- a/src/glsl/builtin_functions.cpp +++ b/src/glsl/builtin_functions.cpp @@ -532,6 +532,7 @@ private: B2(ldexp) B2(frexp) B1(uaddCarry) + B1(usubBorrow) #undef B0 #undef B1 #undef B2 @@ -1954,6 +1955,12 @@ builtin_builder::create_builtins() _uaddCarry(glsl_type::uvec3_type), _uaddCarry(glsl_type::uvec4_type), NULL); + add_function("usubBorrow", + _usubBorrow(glsl_type::uint_type), + _usubBorrow(glsl_type::uvec2_type), + _usubBorrow(glsl_type::uvec3_type), + _usubBorrow(glsl_type::uvec4_type), + NULL); #undef F #undef FI #undef FIU @@ -3741,6 +3748,20 @@ builtin_builder::_uaddCarry(const glsl_type *type) return sig; } + +ir_function_signature * +builtin_builder::_usubBorrow(const glsl_type *type) +{ + ir_variable *x = in_var(type, "x"); + ir_variable *y = in_var(type, "y"); + ir_variable *borrow = out_var(type, "borrow"); + MAKE_SIG(type, gpu_shader5, 3, x, y, borrow); + + body.emit(assign(borrow, ir_builder::borrow(x, y))); + body.emit(ret(sub(x, y))); + + return sig; +} /** @} */ /******************************************************************************/ |