From fe66d06cddc60124eb7cd6ba251749432a47111c Mon Sep 17 00:00:00 2001
From: Anton Khirnov <anton@khirnov.net>
Date: Wed, 9 Jan 2019 23:17:06 +0100
Subject: residual_calc.asm: implement writing partial blocks

Avoid overwriting anything over the specified line size.
---
 residual_calc.asm | 29 +++++++++++++++++++++++++++--
 1 file changed, 27 insertions(+), 2 deletions(-)

(limited to 'residual_calc.asm')

diff --git a/residual_calc.asm b/residual_calc.asm
index 289c3fb..f6f34f3 100644
--- a/residual_calc.asm
+++ b/residual_calc.asm
@@ -208,10 +208,35 @@ SECTION .text
     RES_ADD_DIFF_MIXED     stencil
 
     ; store the result
-    movu [dstq + offsetq], m0
     add offsetq, mmsize
-    js .loop
+    jg .store_partial
 
+    ; store full block
+    movu [dstq + offsetq - mmsize], m0
+    js .loop
+    jmp .finish
+
+.store_partial:
+    sub offsetq, ELEM_SIZE
+    jz .store1
+    sub offsetq, ELEM_SIZE
+    jz .store2
+
+.store3:
+    ; offsetq is now mmsize-2 after the write position
+    movu [dstq + offsetq - mmsize + 2 * ELEM_SIZE], xm0
+    vextractf128 xm0, m0, 1
+    movq [dstq + offsetq - mmsize + 4 * ELEM_SIZE], xm0
+    jmp .finish
+.store2:
+    ; offsetq is now mmsize-2 after the write position
+    movu [dstq + offsetq - mmsize + 2 * ELEM_SIZE], xm0
+    jmp .finish
+.store1:
+    ; offsetq is now mmsize-1 after the write position
+    movq [dstq + offsetq - mmsize + ELEM_SIZE], xm0
+
+.finish:
     RET
 %endmacro
 
-- 
cgit v1.2.3