diff --git a/src/buildvm_arm.dasc b/src/buildvm_arm.dasc
index 7b2d3ce7..aa55e549 100644
--- a/src/buildvm_arm.dasc
+++ b/src/buildvm_arm.dasc
@@ -457,8 +457,20 @@ static void build_subroutines(BuildCtx *ctx)
   |  // BASE = base, RA = resultptr, CARG4 = meta base
   |   bx CARG1
   |
-  |->cont_cat:
-  |  NYI
+  |->cont_cat:				// RA = resultptr, CARG4 = meta base
+  |  ldr INS, [PC, #-4]
+  |   sub CARG2, CARG4, #16
+  |   ldrd CARG34, [RA]
+  |     str BASE, L->base
+  |  decode_RB8 RC, INS
+  |   decode_RA8 RA, INS
+  |  add CARG1, BASE, RC
+  |  subs CARG1, CARG2, CARG1
+  |   strdne CARG34, [CARG2]
+  |   movne CARG3, CARG1
+  |  bne ->BC_CAT_Z
+  |   strd CARG34, [BASE, RA]
+  |  b ->cont_nop
   |
   |//-- Table indexing metamethods -----------------------------------------
   |
@@ -1846,7 +1858,27 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defop)
     break;
 
   case BC_CAT:
-    |  NYI
+    |  decode_RB8 RC, INS
+    |   decode_RC8 RB, INS
+    |  // RA = dst*8, RC = src_start*8, RB = src_end*8  (note: RB/RC swapped!)
+    |  sub CARG3, RB, RC
+    |   str BASE, L->base
+    |  add CARG2, BASE, RB
+    |->BC_CAT_Z:
+    |  // RA = dst*8, RC = src_start*8, CARG2 = top-1
+    |  mov CARG1, L
+    |   str PC, SAVE_PC
+    |  lsr CARG3, CARG3, #3
+    |  bl extern lj_meta_cat		// (lua_State *L, TValue *top, int left)
+    |  // Returns NULL (finished) or TValue * (metamethod).
+    |  ldr BASE, L->base
+    |  cmp CRET1, #0
+    |  bne ->vmeta_binop
+    |  ldrd CARG34, [BASE, RC]
+    |   ins_next1
+    |   ins_next2
+    |  strd CARG34, [BASE, RA]		// Copy result to RA.
+    |   ins_next3
     break;
 
   /* -- Constant ops ------------------------------------------------------ */