diff --git a/target/arm/tcg/a64.decode b/target/arm/tcg/a64.decode
index 8e2949d2361..05396945062 100644
--- a/target/arm/tcg/a64.decode
+++ b/target/arm/tcg/a64.decode
@@ -727,6 +727,15 @@ ANDS_r          . 11 01010 .. . ..... ...... ..... .....    @logic_shift
 
 # Add/subtract (shifted reg)
 # Add/subtract (extended reg)
+
+&addsub_ext     rd rn rm sf sa st
+@addsub_ext     sf:1 .. ........ rm:5 st:3 sa:3 rn:5 rd:5   &addsub_ext
+
+ADD_ext         . 00 01011001 ..... ... ... ..... .....     @addsub_ext
+SUB_ext         . 10 01011001 ..... ... ... ..... .....     @addsub_ext
+ADDS_ext        . 01 01011001 ..... ... ... ..... .....     @addsub_ext
+SUBS_ext        . 11 01011001 ..... ... ... ..... .....     @addsub_ext
+
 # Add/subtract (carry)
 # Rotate right into flags
 # Evaluate into flags
diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index ecc8899dd84..8f777875fe0 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -7864,57 +7864,27 @@ TRANS(AND_r, do_logic_reg, a, tcg_gen_and_i64, tcg_gen_andc_i64, false)
 TRANS(ANDS_r, do_logic_reg, a, tcg_gen_and_i64, tcg_gen_andc_i64, true)
 TRANS(EOR_r, do_logic_reg, a, tcg_gen_xor_i64, tcg_gen_eqv_i64, false)
 
-/*
- * Add/subtract (extended register)
- *
- *  31|30|29|28       24|23 22|21|20   16|15  13|12  10|9  5|4  0|
- * +--+--+--+-----------+-----+--+-------+------+------+----+----+
- * |sf|op| S| 0 1 0 1 1 | opt | 1|  Rm   |option| imm3 | Rn | Rd |
- * +--+--+--+-----------+-----+--+-------+------+------+----+----+
- *
- *  sf: 0 -> 32bit, 1 -> 64bit
- *  op: 0 -> add  , 1 -> sub
- *   S: 1 -> set flags
- * opt: 00
- * option: extension type (see DecodeRegExtend)
- * imm3: optional shift to Rm
- *
- * Rd = Rn + LSL(extend(Rm), amount)
- */
-static void disas_add_sub_ext_reg(DisasContext *s, uint32_t insn)
+static bool do_addsub_ext(DisasContext *s, arg_addsub_ext *a,
+                          bool sub_op, bool setflags)
 {
-    int rd = extract32(insn, 0, 5);
-    int rn = extract32(insn, 5, 5);
-    int imm3 = extract32(insn, 10, 3);
-    int option = extract32(insn, 13, 3);
-    int rm = extract32(insn, 16, 5);
-    int opt = extract32(insn, 22, 2);
-    bool setflags = extract32(insn, 29, 1);
-    bool sub_op = extract32(insn, 30, 1);
-    bool sf = extract32(insn, 31, 1);
+    TCGv_i64 tcg_rm, tcg_rn, tcg_rd, tcg_result;
 
-    TCGv_i64 tcg_rm, tcg_rn; /* temps */
-    TCGv_i64 tcg_rd;
-    TCGv_i64 tcg_result;
-
-    if (imm3 > 4 || opt != 0) {
-        unallocated_encoding(s);
-        return;
+    if (a->sa > 4) {
+        return false;
     }
 
     /* non-flag setting ops may use SP */
     if (!setflags) {
-        tcg_rd = cpu_reg_sp(s, rd);
+        tcg_rd = cpu_reg_sp(s, a->rd);
     } else {
-        tcg_rd = cpu_reg(s, rd);
+        tcg_rd = cpu_reg(s, a->rd);
     }
-    tcg_rn = read_cpu_reg_sp(s, rn, sf);
+    tcg_rn = read_cpu_reg_sp(s, a->rn, a->sf);
 
-    tcg_rm = read_cpu_reg(s, rm, sf);
-    ext_and_shift_reg(tcg_rm, tcg_rm, option, imm3);
+    tcg_rm = read_cpu_reg(s, a->rm, a->sf);
+    ext_and_shift_reg(tcg_rm, tcg_rm, a->st, a->sa);
 
     tcg_result = tcg_temp_new_i64();
-
     if (!setflags) {
         if (sub_op) {
             tcg_gen_sub_i64(tcg_result, tcg_rn, tcg_rm);
@@ -7923,19 +7893,25 @@ static void disas_add_sub_ext_reg(DisasContext *s, uint32_t insn)
         }
     } else {
         if (sub_op) {
-            gen_sub_CC(sf, tcg_result, tcg_rn, tcg_rm);
+            gen_sub_CC(a->sf, tcg_result, tcg_rn, tcg_rm);
         } else {
-            gen_add_CC(sf, tcg_result, tcg_rn, tcg_rm);
+            gen_add_CC(a->sf, tcg_result, tcg_rn, tcg_rm);
         }
     }
 
-    if (sf) {
+    if (a->sf) {
         tcg_gen_mov_i64(tcg_rd, tcg_result);
     } else {
         tcg_gen_ext32u_i64(tcg_rd, tcg_result);
     }
+    return true;
 }
 
+TRANS(ADD_ext, do_addsub_ext, a, false, false)
+TRANS(SUB_ext, do_addsub_ext, a, true, false)
+TRANS(ADDS_ext, do_addsub_ext, a, false, true)
+TRANS(SUBS_ext, do_addsub_ext, a, true, true)
+
 /*
  * Add/subtract (shifted register)
  *
@@ -8374,8 +8350,7 @@ static void disas_data_proc_reg(DisasContext *s, uint32_t insn)
     if (!op1) {
         if (op2 & 8) {
             if (op2 & 1) {
-                /* Add/sub (extended register) */
-                disas_add_sub_ext_reg(s, insn);
+                goto do_unallocated;
             } else {
                 /* Add/sub (shifted register) */
                 disas_add_sub_reg(s, insn);
