From 7adacf5a7bc0ebe1e33bf917c627fb641adaef92 Mon Sep 17 00:00:00 2001
From: Anton Mitrokhin <anton.mitrokhin@phystech.edu>
Date: Thu, 14 Aug 2014 17:27:56 +0400
Subject: [PATCH] 64 bit gather/scatter fix for knc.h

---
 examples/intrinsics/knc.h | 29 +++++++++++++++++++----------
 1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/examples/intrinsics/knc.h b/examples/intrinsics/knc.h
index e674f409..3d1bcafc 100644
--- a/examples/intrinsics/knc.h
+++ b/examples/intrinsics/knc.h
@@ -40,10 +40,11 @@
 #include <immintrin.h>
 #include <zmmintrin.h>
 
+#define INT32_MIN   (-0x7fffffff - 1)
+
 #include <iostream> // for operator<<(m512[i])
 #include <iomanip>  // for operator<<(m512[i])
 
-
 #define FORCEINLINE __forceinline
 #ifdef _MSC_VER
 #define PRE_ALIGN(x)  /*__declspec(align(x))*/
@@ -1749,6 +1750,8 @@ __gather_base_offsets32_double(uint8_t *base, uint32_t scale, __vec16_i32 offset
 static FORCEINLINE __vec16_f
 __gather_base_offsets64_float(uint8_t *_base, uint32_t scale, __vec16_i64 offsets,
                               __vec16_i1 mask) {
+
+  const __vec16_i32 signed_offsets = _mm512_add_epi32(offsets.v_lo, __smear_i32<__vec16_i32>((int32_t)INT32_MIN));
     // There is no gather instruction with 64-bit offsets in KNC.
     // We have to manually iterate over the upper 32 bits ;-)
     __vec16_i1 still_to_do = mask;
@@ -1759,10 +1762,10 @@ __gather_base_offsets64_float(uint8_t *_base, uint32_t scale, __vec16_i64 offset
         __vec16_i1 match = _mm512_mask_cmp_epi32_mask(mask,offsets.v_hi,
                                                       __smear_i32<__vec16_i32>((int32_t)hi32),
                                                       _MM_CMPINT_EQ);
-        
         void * base = (void*)((unsigned long)_base  +
-                              ((scale*(unsigned long)hi32) << 32));
-        ret = _mm512_mask_i32extgather_ps(ret, match, offsets.v_lo, base,
+            ((scale*(unsigned long)hi32) << 32) + scale*(unsigned long)(-(long)INT32_MIN));
+        
+        ret = _mm512_mask_i32extgather_ps(ret, match, signed_offsets, base,
                                           _MM_UPCONV_PS_NONE, scale,
                                           _MM_HINT_NONE);
         still_to_do = _mm512_kxor(match, still_to_do);
@@ -1776,6 +1779,8 @@ static FORCEINLINE __vec16_i8
 __gather_base_offsets64_i8(uint8_t *_base, uint32_t scale, __vec16_i64 offsets,
                            __vec16_i1 mask) 
 { 
+
+    const __vec16_i32 signed_offsets = _mm512_add_epi32(offsets.v_lo, __smear_i32<__vec16_i32>((int32_t)INT32_MIN));
     __vec16_i1 still_to_do = mask;
     __vec16_i32 tmp;
     while (still_to_do) {
@@ -1786,8 +1791,8 @@ __gather_base_offsets64_i8(uint8_t *_base, uint32_t scale, __vec16_i64 offsets,
                                                       _MM_CMPINT_EQ);
     
         void * base = (void*)((unsigned long)_base  +
-                              ((scale*(unsigned long)hi32) << 32));    
-        tmp = _mm512_mask_i32extgather_epi32(tmp, match, offsets.v_lo, base,
+            ((scale*(unsigned long)hi32) << 32) + scale*(unsigned long)(-(long)INT32_MIN));
+        tmp = _mm512_mask_i32extgather_epi32(tmp, match, signed_offsets, base,
                                              _MM_UPCONV_EPI32_SINT8, scale,
                                              _MM_HINT_NONE);
         still_to_do = _mm512_kxor(match,still_to_do);
@@ -1802,6 +1807,8 @@ static FORCEINLINE void
 __scatter_base_offsets64_float(uint8_t *_base, uint32_t scale, __vec16_i64 offsets,
                                __vec16_f value,
                                __vec16_i1 mask) { 
+
+    const __vec16_i32 signed_offsets = _mm512_add_epi32(offsets.v_lo, __smear_i32<__vec16_i32>((int32_t)INT32_MIN));
     __vec16_i1 still_to_do = mask;
     while (still_to_do) {
         int first_active_lane = _mm_tzcnt_32((int)still_to_do);
@@ -1811,8 +1818,8 @@ __scatter_base_offsets64_float(uint8_t *_base, uint32_t scale, __vec16_i64 offse
                                                       _MM_CMPINT_EQ);
 
         void * base = (void*)((unsigned long)_base  +
-                              ((scale*(unsigned long)hi32) << 32));    
-        _mm512_mask_i32extscatter_ps(base, match, offsets.v_lo, 
+            ((scale*(unsigned long)hi32) << 32) + scale*(unsigned long)(-(long)INT32_MIN));   
+        _mm512_mask_i32extscatter_ps(base, match, signed_offsets, 
                                      value,
                                      _MM_DOWNCONV_PS_NONE, scale,
                                      _MM_HINT_NONE);
@@ -1824,6 +1831,8 @@ static FORCEINLINE void
 __scatter_base_offsets64_i32(uint8_t *_base, uint32_t scale, __vec16_i64 offsets,
                              __vec16_i32 value,
                              __vec16_i1 mask) { 
+
+    const __vec16_i32 signed_offsets = _mm512_add_epi32(offsets.v_lo, __smear_i32<__vec16_i32>((int32_t)INT32_MIN));
     __vec16_i1 still_to_do = mask;
     while (still_to_do) {
         int first_active_lane = _mm_tzcnt_32((int)still_to_do);
@@ -1833,8 +1842,8 @@ __scatter_base_offsets64_i32(uint8_t *_base, uint32_t scale, __vec16_i64 offsets
                                                       _MM_CMPINT_EQ);
     
         void * base = (void*)((unsigned long)_base  +
-                              ((scale*(unsigned long)hi32) << 32));    
-        _mm512_mask_i32extscatter_epi32(base, match, offsets.v_lo, 
+            ((scale*(unsigned long)hi32) << 32) + scale*(unsigned long)(-(long)INT32_MIN));  
+        _mm512_mask_i32extscatter_epi32(base, match, signed_offsets, 
                                         value,
                                         _MM_DOWNCONV_EPI32_NONE, scale,
                                         _MM_HINT_NONE);