--- jdhuff.c
+++ jdhuff.c
@@ -489,7 +489,7 @@
 #define AVOID_TABLES
 #ifdef AVOID_TABLES
 
-#define HUFF_EXTEND(x,s)  ((x) + ((((x) - (1<<((s)-1))) >> 31) & (((-1)<<(s)) + 1)))
+#define HUFF_EXTEND(x,s)  ((x) + ((((x) - (1<<((s)-1))) >> 31) & (((unsigned)-1<<(s)) + 1)))
 
 #else
 
--- jdphuff.c
+++ jdphuff.c
@@ -201,7 +201,7 @@
 #define AVOID_TABLES
 #ifdef AVOID_TABLES
 
-#define HUFF_EXTEND(x,s)  ((x) < (1<<((s)-1)) ? (x) + (((-1)<<(s)) + 1) : (x))
+#define HUFF_EXTEND(x,s)  ((x) < (1<<((s)-1)) ? (x) + (((unsigned)-1<<(s)) + 1) : (x))
 
 #else
 
@@ -334,7 +334,7 @@
       s += state.last_dc_val[ci];
       state.last_dc_val[ci] = s;
       /* Scale and output the coefficient (assumes jpeg_natural_order[0]=0) */
-      (*block)[0] = (JCOEF) (s << Al);
+      (*block)[0] = (JCOEF) ((unsigned)s << Al);
     }
 
     /* Completed MCU, so update state */
@@ -402,7 +402,7 @@
 	  r = GET_BITS(s);
 	  s = HUFF_EXTEND(r, s);
 	  /* Scale and output coefficient in natural (dezigzagged) order */
-	  (*block)[jpeg_natural_order[k]] = (JCOEF) (s << Al);
+	  (*block)[jpeg_natural_order[k]] = (JCOEF) ((unsigned)s << Al);
 	} else {
 	  if (r == 15) {	/* ZRL */
 	    k += 15;		/* skip 15 zeroes in band */
@@ -494,7 +494,7 @@
   phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
   int Se = cinfo->Se;
   int p1 = 1 << cinfo->Al;	/* 1 in the bit position being coded */
-  int m1 = (-1) << cinfo->Al;	/* -1 in the bit position being coded */
+  int m1 = (unsigned)-1 << cinfo->Al;	/* -1 in the bit position being coded */
   register int s, k, r;
   unsigned int EOBRUN;
   JBLOCKROW block;