diff --git a/src/cmd/as/as.c b/src/cmd/as/as.c
index 0df415c..71d868c 100644
--- a/src/cmd/as/as.c
+++ b/src/cmd/as/as.c
@@ -1238,7 +1238,7 @@ void emitword (w, r, clobber_reg)
         reorder_word = w;
         reorder_rel = *r;
         reorder_full = 1;
-        reorder_clobber = clobber_reg;
+        reorder_clobber = clobber_reg & 15;
     } else {
         fputword (w, sfile[segm]);
         fputrel (r, rfile[segm]);
@@ -1317,10 +1317,9 @@ void makecmd (opcode, type, emitfunc)
     unsigned opcode;
     void (*emitfunc) (unsigned, struct reloc*);
 {
-    register int clex;
-    register unsigned offset;
+    unsigned offset, orig_opcode = 0;
     struct reloc relinfo;
-    int cval, segment, clobber_reg, negate_literal;
+    int clex, cval, segment, clobber_reg, negate_literal;
 
     offset = 0;
     relinfo.flags = RABS;
@@ -1480,6 +1479,7 @@ frs1:   clex = getlex (&cval);
                 cval = (opcode >> 11) & 31;         /* get 1-st register */
                 newop |= cval << 16;                /* set 1-st register */
                 newop |= opcode & (31 << 21);       /* set 2-nd register */
+                orig_opcode = opcode;
                 opcode = newop;
                 type = FRT1 | FRS2 | FOFF16 | FMOD;
                 goto foff16;
@@ -1572,6 +1572,8 @@ fsa:    offset = getexpr (&segment);
         }
     } else if (type & (FOFF16 | FOFF18 | FAOFF18 | FAOFF28 | FHIGH16)) {
         /* Relocatable offset */
+        int valid_range;
+
         if ((type & (FOFF16 | FOFF18 | FHIGH16)) && getlex (&cval) != ',')
             uerror ("comma expected");
 foff16: expr_flags = 0;
@@ -1589,7 +1591,48 @@ foff16: expr_flags = 0;
             relinfo.flags |= RGPREL;
         switch (type & (FOFF16 | FOFF18 | FAOFF18 | FAOFF28 | FHIGH16)) {
         case FOFF16:                    /* low 16-bit byte address */
-            opcode |= offset & 0xffff;
+            /* Test whether the immediate is in valid range
+             * for the opcode. */
+            switch (opcode & 0xfc000000) {
+            case 0x20000000:                    // addi
+            case 0x24000000:                    // addiu
+            case 0x28000000:                    // slti
+            case 0x2c000000:                    // sltiu
+                /* 16-bit signed value. */
+                valid_range = (offset >= -0x8000) && (offset <= 0x7fff);
+                break;
+            case 0x30000000:                    // andi
+            case 0x34000000:                    // ori
+            case 0x38000000:                    // xori
+            default:
+                /* 16-bit unsigned value. */
+                valid_range = (offset >= 0) && (offset <= 0xffff);
+                break;
+            }
+            if (valid_range) {
+                opcode |= offset & 0xffff;
+            } else if (orig_opcode == 0) {
+                uerror ("value out of range");
+            } else {
+                /* Convert back to 3-reg opcode.
+                 * Insert an extra LI instruction. */
+                if (segment != SABS)
+                    uerror ("absolute value required");
+
+                if (offset <= 0xffff) {
+                    /* ori $1, $zero, value */
+                    emitword (0x34010000 | offset, &relabs, 1);
+                } else if (offset >= -0x8000) {
+                    /* addiu $1, $zero, value */
+                    emitword (0x24010000 | (offset & 0xffff), &relabs, 1);
+                } else {
+                    /* lui $1, value[31:16]
+                     * ori $1, $1, value[15:0]) */
+                    emitword (0x3c010000 | (offset >> 16), &relabs, 1);
+                    emitword (0x34210000 | (offset & 0xffff), &relabs, 1);
+                }
+                opcode = orig_opcode | 0x10000;
+            }
             break;
         case FHIGH16:                   /* high 16-bit byte address */
             if (expr_flags & EXPR_HI) {