diff --git a/pipi/filter/convolution_template.h b/pipi/filter/convolution_template.h
index 976fd9b..595d1e7 100644
--- a/pipi/filter/convolution_template.h
+++ b/pipi/filter/convolution_template.h
@@ -57,13 +57,13 @@ static pipi_image_t *FUNC1(pipi_image_t *src, int m, int n, double mat[])
                 for(j = 0; j < n; j++)
                 {
                     y2 = y + j - n / 2;
-                    if(y2 < 0) y2 = FLAG_WRAP ? (h - 1 - (-y2 - 1) % h) : 0;
+                    if(y2 < 0) y2 = FLAG_WRAP ? h - 1 - ((-y2 - 1) % h) : 0;
                     else if(y2 >= h) y2 = FLAG_WRAP ? y2 % h : h - 1;
 
                     for(i = 0; i < m; i++)
                     {
                         x2 = x + i - m / 2;
-                        if(x2 < 0) x2 = FLAG_WRAP ? (w - 1 - (-x2 - 1) % w) : 0;
+                        if(x2 < 0) x2 = FLAG_WRAP ? w - 1 - ((-x2 - 1) % w) : 0;
                         else if(x2 >= w) x2 = FLAG_WRAP ? x2 % w : w - 1;
 
                         Y += mat[j * m + i] * srcdata[y2 * w + x2];
@@ -80,7 +80,7 @@ static pipi_image_t *FUNC1(pipi_image_t *src, int m, int n, double mat[])
                 for(j = 0; j < n; j++)
                 {
                     y2 = y + j - n / 2;
-                    if(y2 < 0) y2 = FLAG_WRAP ? (h - 1 - (-y2 - 1) % h) : 0;
+                    if(y2 < 0) y2 = FLAG_WRAP ? h - 1 - ((-y2 - 1) % h) : 0;
                     else if(y2 >= h) y2 = FLAG_WRAP ? y2 % h : h - 1;
 
                     for(i = 0; i < m; i++)
@@ -88,7 +88,7 @@ static pipi_image_t *FUNC1(pipi_image_t *src, int m, int n, double mat[])
                         double f = mat[j * m + i];
 
                         x2 = x + i - m / 2;
-                        if(x2 < 0) x2 = FLAG_WRAP ? (w - 1 - (-x2 - 1) % w) : 0;
+                        if(x2 < 0) x2 = FLAG_WRAP ? w - 1 - ((-x2 - 1) % w) : 0;
                         else if(x2 >= w) x2 = FLAG_WRAP ? x2 % w : w - 1;
 
                         R += f * srcdata[(y2 * w + x2) * 4];
@@ -142,7 +142,7 @@ static pipi_image_t *FUNC2(pipi_image_t *src,
                 for(i = 0; i < m; i++)
                 {
                     x2 = x + i - m / 2;
-                    if(x2 < 0) x2 = FLAG_WRAP ? (w - 1 - (-x2 - 1) % w) : 0;
+                    if(x2 < 0) x2 = FLAG_WRAP ? w - 1 - ((-x2 - 1) % w) : 0;
                     else if(x2 >= w) x2 = FLAG_WRAP ? x2 % w : w - 1;
 
                     Y += hvec[i] * srcdata[y * w + x2];
@@ -160,7 +160,7 @@ static pipi_image_t *FUNC2(pipi_image_t *src,
                     double f = hvec[i];
 
                     x2 = x + i - m / 2;
-                    if(x2 < 0) x2 = FLAG_WRAP ? (w - 1 - (-x2 - 1) % w) : 0;
+                    if(x2 < 0) x2 = FLAG_WRAP ? w - 1 - ((-x2 - 1) % w) : 0;
                     else if(x2 >= w) x2 = FLAG_WRAP ? x2 % w : w - 1;
 
                     R += f * srcdata[(y * w + x2) * 4];
@@ -187,7 +187,7 @@ static pipi_image_t *FUNC2(pipi_image_t *src,
                 for(j = 0; j < n; j++)
                 {
                     y2 = y + j - n / 2;
-                    if(y2 < 0) y2 = FLAG_WRAP ? (h - 1 - (-y2 - 1) % h) : 0;
+                    if(y2 < 0) y2 = FLAG_WRAP ? h - 1 - ((-y2 - 1) % h) : 0;
                     else if(y2 >= h) y2 = FLAG_WRAP ? y2 % h : h - 1;
 
                     Y += vvec[j] * buffer[y2 * w + x];
@@ -205,7 +205,7 @@ static pipi_image_t *FUNC2(pipi_image_t *src,
                     double f = vvec[j];
 
                     y2 = y + j - n / 2;
-                    if(y2 < 0) y2 = FLAG_WRAP ? (h - 1 - (-y2 - 1) % h) : 0;
+                    if(y2 < 0) y2 = FLAG_WRAP ? h - 1 - ((-y2 - 1) % h) : 0;
                     else if(y2 >= h) y2 = FLAG_WRAP ? y2 % h : h - 1;
 
                     R += f * buffer[(y2 * w + x) * 4];