From 155eb109a8bb21e82992b628e02304448b387a7f Mon Sep 17 00:00:00 2001
From: Recep Aslantas <info@recp.me>
Date: Sun, 25 Apr 2021 03:49:35 +0300
Subject: [PATCH] arm, neon: neon/fma support for glm_mul_rot()

---
 include/cglm/affine-mat.h       |  2 ++
 include/cglm/simd/neon/affine.h | 29 +++++++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/include/cglm/affine-mat.h b/include/cglm/affine-mat.h
index 8383283..c555eae 100644
--- a/include/cglm/affine-mat.h
+++ b/include/cglm/affine-mat.h
@@ -109,6 +109,8 @@ void
 glm_mul_rot(mat4 m1, mat4 m2, mat4 dest) {
 #if defined( __SSE__ ) || defined( __SSE2__ )
   glm_mul_rot_sse2(m1, m2, dest);
+#elif defined(CGLM_NEON_FP)
+  glm_mul_rot_neon(m1, m2, dest);
 #else
   float a00 = m1[0][0], a01 = m1[0][1], a02 = m1[0][2], a03 = m1[0][3],
         a10 = m1[1][0], a11 = m1[1][1], a12 = m1[1][2], a13 = m1[1][3],
diff --git a/include/cglm/simd/neon/affine.h b/include/cglm/simd/neon/affine.h
index 90c9ab4..b511083 100644
--- a/include/cglm/simd/neon/affine.h
+++ b/include/cglm/simd/neon/affine.h
@@ -47,5 +47,34 @@ glm_mul_neon(mat4 m1, mat4 m2, mat4 dest) {
   glmm_store(dest[3], v3);
 }
 
+CGLM_INLINE
+void
+glm_mul_rot_neon(mat4 m1, mat4 m2, mat4 dest) {
+  /* D = R * L (Column-Major) */
+
+  glmm_128 l0, l1, l2, r0, r1, r2, v0, v1, v2;
+
+  l0 = glmm_load(m1[0]);    r0 = glmm_load(m2[0]);
+  l1 = glmm_load(m1[1]);    r1 = glmm_load(m2[1]);
+  l2 = glmm_load(m1[2]);    r2 = glmm_load(m2[2]);
+
+  v0 = vmulq_f32(glmm_splat_x(r0), l0);
+  v1 = vmulq_f32(glmm_splat_x(r1), l0);
+  v2 = vmulq_f32(glmm_splat_x(r2), l0);
+
+  v0 = glmm_fmadd(glmm_splat_y(r0), l1, v0);
+  v1 = glmm_fmadd(glmm_splat_y(r1), l1, v1);
+  v2 = glmm_fmadd(glmm_splat_y(r2), l1, v2);
+
+  v0 = glmm_fmadd(glmm_splat_z(r0), l2, v0);
+  v1 = glmm_fmadd(glmm_splat_z(r1), l2, v1);
+  v2 = glmm_fmadd(glmm_splat_z(r2), l2, v2);
+
+  glmm_store(dest[0], v0);
+  glmm_store(dest[1], v1);
+  glmm_store(dest[2], v2);
+  glmm_store(dest[3], glmm_load(m1[3]));
+}
+
 #endif
 #endif /* cglm_affine_neon_h */