[Mesa-dev] [RFC 02/11] glsl: Add "built-in" function to do neg(fp64)

[Elie Tournier]

Signed-off-by: Elie Tournier <elie.tournier at collabora.com>
---
 src/compiler/glsl/builtin_float64.h     | 19 +++++++++++++++++++
 src/compiler/glsl/builtin_functions.cpp |  4 ++++
 src/compiler/glsl/builtin_functions.h   |  3 +++
 src/compiler/glsl/float64.glsl          | 10 ++++++++++
 4 files changed, 36 insertions(+)

diff --git a/src/compiler/glsl/builtin_float64.h b/src/compiler/glsl/builtin_float64.h
index c1ec89d210..6df91e10f5 100644
--- a/src/compiler/glsl/builtin_float64.h
+++ b/src/compiler/glsl/builtin_float64.h
@@ -17,3 +17,22 @@ fabs64(void *mem_ctx, builtin_available_predicate avail)
    sig->replace_parameters(&sig_parameters);
    return sig;
 }
+ir_function_signature *
+fneg64(void *mem_ctx, builtin_available_predicate avail)
+{
+   ir_function_signature *const sig =
+      new(mem_ctx) ir_function_signature(glsl_type::uvec2_type, avail);
+   ir_factory body(&sig->body, mem_ctx);
+   sig->is_defined = true;
+
+   exec_list sig_parameters;
+
+   ir_variable *const r000C = new(mem_ctx) ir_variable(glsl_type::uvec2_type, "a", ir_var_function_in);
+   sig_parameters.push_tail(r000C);
+   body.emit(assign(r000C, bit_xor(swizzle_x(r000C), body.constant(2147483648u)), 0x01));
+
+   body.emit(ret(r000C));
+
+   sig->replace_parameters(&sig_parameters);
+   return sig;
+}
diff --git a/src/compiler/glsl/builtin_functions.cpp b/src/compiler/glsl/builtin_functions.cpp
index b0b1781725..a189b84190 100644
--- a/src/compiler/glsl/builtin_functions.cpp
+++ b/src/compiler/glsl/builtin_functions.cpp
@@ -3133,6 +3133,10 @@ builtin_builder::create_builtins()
                 generate_ir::fabs64(mem_ctx, integer_functions_supported),
                 NULL);
 
+   add_function("__builtin_fneg64",
+                generate_ir::fneg64(mem_ctx, integer_functions_supported),
+                NULL);
+
 #undef F
 #undef FI
 #undef FIUD_VEC
diff --git a/src/compiler/glsl/builtin_functions.h b/src/compiler/glsl/builtin_functions.h
index abe02d97b6..37c6cc33c2 100644
--- a/src/compiler/glsl/builtin_functions.h
+++ b/src/compiler/glsl/builtin_functions.h
@@ -66,6 +66,9 @@ sign64(void *mem_ctx, builtin_available_predicate avail);
 ir_function_signature *
 fabs64(void *mem_ctx, builtin_available_predicate avail);
 
+ir_function_signature *
+fneg64(void *mem_ctx, builtin_available_predicate avail);
+
 }
 
 #endif /* BULITIN_FUNCTIONS_H */
diff --git a/src/compiler/glsl/float64.glsl b/src/compiler/glsl/float64.glsl
index b8f0c2e444..82875e9407 100644
--- a/src/compiler/glsl/float64.glsl
+++ b/src/compiler/glsl/float64.glsl
@@ -26,3 +26,13 @@ fabs64( uvec2 a )
     a.x &= 0x7FFFFFFFu;
     return a;
 }
+
+/* Negate value of a Float64 :
+ * Toggle the sign bit
+ */
+uvec2
+fneg64( uvec2 a )
+{
+    a.x ^= (1u<<31);
+    return a;
+}
-- 
2.11.0