diff --git a/qoi.h b/qoi.h
index 6734ac4..1526271 100644
--- a/qoi.h
+++ b/qoi.h
@@ -339,10 +339,10 @@ typedef union {
 static const unsigned char qoi_padding[8] = {0,0,0,0,0,0,0,1};
 
 static void qoi_write_32(unsigned char *bytes, int *p, unsigned int v) {
-	bytes[(*p)++] = (0xff000000 & v) >> 24;
-	bytes[(*p)++] = (0x00ff0000 & v) >> 16;
-	bytes[(*p)++] = (0x0000ff00 & v) >> 8;
-	bytes[(*p)++] = (0x000000ff & v);
+	bytes[(*p)++] = (v >> 24) & 0xff;
+	bytes[(*p)++] = (v >> 16) & 0xff;
+	bytes[(*p)++] = (v >>  8) & 0xff;
+	bytes[(*p)++] = (v >>  0) & 0xff;
 }
 
 static unsigned int qoi_read_32(const unsigned char *bytes, int *p) {
@@ -415,7 +415,7 @@ void *qoi_encode(const void *data, const qoi_desc *desc, int *out_len) {
 		if (px.v == px_prev.v) {
 			run++;
 			if (run == 62 || px_pos == px_end) {
-				bytes[p++] = QOI_OP_RUN | (run - 1);
+				bytes[p++] = QOI_OP_RUN | (unsigned char)(run - 1);
 				run = 0;
 			}
 		}
@@ -423,14 +423,14 @@ void *qoi_encode(const void *data, const qoi_desc *desc, int *out_len) {
 			int index_pos;
 
 			if (run > 0) {
-				bytes[p++] = QOI_OP_RUN | (run - 1);
+				bytes[p++] = QOI_OP_RUN | (unsigned char)(run - 1);
 				run = 0;
 			}
 
 			index_pos = QOI_COLOR_HASH(px) % 64;
 
 			if (index[index_pos].v == px.v) {
-				bytes[p++] = QOI_OP_INDEX | index_pos;
+				bytes[p++] = QOI_OP_INDEX | (unsigned char)index_pos;
 			}
 			else {
 				index[index_pos] = px;
@@ -566,9 +566,9 @@ void *qoi_decode(const void *data, int size, qoi_desc *desc, int channels) {
 			else if ((b1 & QOI_MASK_2) == QOI_OP_LUMA) {
 				int b2 = bytes[p++];
 				int vg = (b1 & 0x3f) - 32;
-				px.rgba.r += vg - 8 + ((b2 >> 4) & 0x0f);
-				px.rgba.g += vg;
-				px.rgba.b += vg - 8 +  (b2       & 0x0f);
+				px.rgba.r += (signed char)(vg - 8 + ((b2 >> 4) & 0x0f));
+				px.rgba.g += (signed char)(vg);
+				px.rgba.b += (signed char)(vg - 8 +  (b2       & 0x0f));
 			}
 			else if ((b1 & QOI_MASK_2) == QOI_OP_RUN) {
 				run = (b1 & 0x3f);
@@ -637,7 +637,7 @@ void *qoi_read(const char *filename, qoi_desc *desc, int channels) {
 		return NULL;
 	}
 
-	bytes_read = fread(data, 1, size, f);
+	bytes_read = (int)fread(data, 1, size, f);
 	fclose(f);
 
 	pixels = qoi_decode(data, bytes_read, desc, channels);