From 7ff76870242b6906b6f3caf22da3c094822ed140 Mon Sep 17 00:00:00 2001
From: Sebastiano Tronto <sebastiano@tronto.net>
Date: Fri, 1 Aug 2025 23:32:19 +0200
Subject: Move is_eo_even to more appropriate module

---
 src/arch/avx2.h     | 14 ++++++++++++++
 src/arch/common.h   |  2 ++
 src/arch/neon.h     | 18 ++++++++++++++++--
 src/arch/portable.h | 11 +++++++++++
 4 files changed, 43 insertions(+), 2 deletions(-)

(limited to 'src/arch')

diff --git a/src/arch/avx2.h b/src/arch/avx2.h
index 3fb46c9..cb9c0cd 100644
--- a/src/arch/avx2.h
+++ b/src/arch/avx2.h
@@ -426,3 +426,17 @@ invcoord_epe(uint64_t i)
 
 	return _mm256_set_epi64x(a, SOLVED_L, 0, SOLVED_L);
 }
+
+STATIC_INLINE bool
+is_eo_even(cube_t cube)
+{
+	uint8_t count;
+	__m256i e;
+
+	e = _mm256_and_si256(cube, EO_AVX2);
+	e = _mm256_srli_si256(e, EOSHIFT);
+
+	count = _mm256_reduce_add_epi8(e);
+
+	return count % 2 == 0;
+}
diff --git a/src/arch/common.h b/src/arch/common.h
index 1c8c0b0..d76b65f 100644
--- a/src/arch/common.h
+++ b/src/arch/common.h
@@ -30,6 +30,8 @@ STATIC_INLINE uint64_t coord_eo(cube_t);
 STATIC_INLINE uint64_t coord_esep(cube_t);
 STATIC_INLINE cube_t invcoord_esep(uint64_t);
 
+STATIC_INLINE bool is_eo_even(cube_t);
+
 STATIC_INLINE void copy_corners(cube_t [static 1], cube_t);
 STATIC_INLINE void copy_edges(cube_t [static 1], cube_t);
 STATIC_INLINE void set_eo(cube_t [static 1], uint64_t);
diff --git a/src/arch/neon.h b/src/arch/neon.h
index 5723b60..2c35c58 100644
--- a/src/arch/neon.h
+++ b/src/arch/neon.h
@@ -1,5 +1,6 @@
-#define CO2_NEON vdup_n_u8(0x60)
-#define COCW_NEON vdup_n_u8(0x20)
+#define CO2_NEON    vdup_n_u8(0x60)
+#define COCW_NEON   vdup_n_u8(0x20)
+#define EO_NEON     vdupq_n_u8(0x10)
 #define PBITS8_NEON vdup_n_u8(PBITS)
 
 STATIC_INLINE uint8x16_t compose_edges_slim(uint8x16_t, uint8x16_t);
@@ -501,3 +502,16 @@ invcoord_epe(uint64_t i)
 		.edge = vcombine_u8(vld1_u8(SOLVED_L), a)
 	};
 }
+
+STATIC_INLINE bool
+is_eo_even(cube_t cube)
+{
+	int8_t count;
+	uint8x16_t e;
+
+	e = vandq_u8(cube.edge, EO_NEON);
+	e = vshrq_n_u8(e, EOSHIFT);
+	count = vaddvq_u8(e);
+
+	return count % 2 == 0;
+}
diff --git a/src/arch/portable.h b/src/arch/portable.h
index 26001ee..d673f15 100644
--- a/src/arch/portable.h
+++ b/src/arch/portable.h
@@ -356,3 +356,14 @@ invcoord_epe(uint64_t i)
         return STATIC_CUBE(0, 1, 2, 3, 4, 5, 6, 7,
             0, 1, 2, 3, 4, 5, 6, 7, e[0]+8, e[1]+8, e[2]+8, e[3]+8);
 }
+
+STATIC_INLINE bool
+is_eo_even(cube_t cube)
+{
+	uint8_t i, count;
+
+	for (i = 0, count = 0; i < 12; i++)
+		count += (cube.edge[i] & EOBIT) >> EOSHIFT;
+
+	return count % 2 == 0;
+}
-- 
cgit v1.3