From 5fb3a91276b2ae6a2fd0bf248d3d84d52c61ea96 Mon Sep 17 00:00:00 2001
From: Nikolay Sivov <nsivov@codeweavers.com>
Date: Wed, 9 Oct 2024 21:27:49 +0200
Subject: [PATCH] vkd3d-shader/hlsl: Implement the modf() intrinsic.

Signed-off-by: Nikolay Sivov <nsivov@codeweavers.com>
---
 Makefile.am                 |  1 +
 libs/vkd3d-shader/hlsl.y    | 30 ++++++++++++++++++++++++++++++
 tests/hlsl/modf.shader_test | 28 ++++++++++++++++++++++++++++
 3 files changed, 59 insertions(+)
 create mode 100644 tests/hlsl/modf.shader_test

diff --git a/Makefile.am b/Makefile.am
index 921702b9..f6e105e0 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -176,6 +176,7 @@ vkd3d_shader_tests = \
 	tests/hlsl/matrix-semantics.shader_test \
 	tests/hlsl/max-min.shader_test \
 	tests/hlsl/minimum-precision.shader_test \
+	tests/hlsl/modf.shader_test \
 	tests/hlsl/mul.shader_test \
 	tests/hlsl/multiple-rt.shader_test \
 	tests/hlsl/nested-arrays.shader_test \
diff --git a/libs/vkd3d-shader/hlsl.y b/libs/vkd3d-shader/hlsl.y
index 2230cd5b..da8a1b87 100644
--- a/libs/vkd3d-shader/hlsl.y
+++ b/libs/vkd3d-shader/hlsl.y
@@ -4260,6 +4260,35 @@ static bool intrinsic_min(struct hlsl_ctx *ctx,
     return !!add_binary_arithmetic_expr(ctx, params->instrs, HLSL_OP2_MIN, params->args[0], params->args[1], loc);
 }
 
+static bool intrinsic_modf(struct hlsl_ctx *ctx,
+        const struct parse_initializer *params, const struct vkd3d_shader_location *loc)
+{
+    struct hlsl_ir_function_decl *func;
+    struct hlsl_type *type;
+    char *body;
+
+    static const char template[] =
+            "%s modf(%s x, out %s ip)\n"
+            "{\n"
+            "    ip = trunc(x);\n"
+            "    return x - ip;\n"
+            "}";
+
+    if (!elementwise_intrinsic_float_convert_args(ctx, params, loc))
+        return false;
+    type = params->args[0]->data_type;
+
+    if (!(body = hlsl_sprintf_alloc(ctx, template,
+            type->name, type->name, type->name)))
+        return false;
+    func = hlsl_compile_internal_function(ctx, "modf", body);
+    vkd3d_free(body);
+    if (!func)
+        return false;
+
+    return !!add_user_call(ctx, func, params, false, loc);
+}
+
 static bool intrinsic_mul(struct hlsl_ctx *ctx,
         const struct parse_initializer *params, const struct vkd3d_shader_location *loc)
 {
@@ -5147,6 +5176,7 @@ intrinsic_functions[] =
     {"mad",                                 3, true,  intrinsic_mad},
     {"max",                                 2, true,  intrinsic_max},
     {"min",                                 2, true,  intrinsic_min},
+    {"modf",                                2, true,  intrinsic_modf},
     {"mul",                                 2, true,  intrinsic_mul},
     {"normalize",                           1, true,  intrinsic_normalize},
     {"pow",                                 2, true,  intrinsic_pow},
diff --git a/tests/hlsl/modf.shader_test b/tests/hlsl/modf.shader_test
new file mode 100644
index 00000000..5a7dc407
--- /dev/null
+++ b/tests/hlsl/modf.shader_test
@@ -0,0 +1,28 @@
+[pixel shader todo(sm<4)]
+float4 v;
+
+float4 main() : sv_target
+{
+    float4 ip;
+    return modf(v, ip);
+}
+
+[test]
+uniform 0 float4 1.2 1.7 -1.2 -1.7
+todo(sm<4) draw quad
+probe (0, 0) rgba (0.2, 0.7, -0.2, -0.7) 4
+
+[pixel shader todo(sm<4)]
+float4 v;
+
+float4 main() : sv_target
+{
+    float4 ip;
+    modf(v, ip);
+    return ip;
+}
+
+[test]
+uniform 0 float4 1.2 2.7 -1.2 -2.7
+todo(sm<4) draw quad
+probe (0, 0) rgba (1.0, 2.0, -1.0, -2.0)