diff --git a/py/asmarm.h b/py/asmarm.h
index 405457d440..5ae952ee8a 100644
--- a/py/asmarm.h
+++ b/py/asmarm.h
@@ -230,6 +230,8 @@ void asm_arm_bx_reg(asm_arm_t *as, uint reg_src);
 #define ASM_STORE16_REG_REG_REG(as, reg_val, reg_base, reg_index) asm_arm_strh_reg_reg_reg((as), (reg_val), (reg_base), (reg_index))
 #define ASM_STORE32_REG_REG_REG(as, reg_val, reg_base, reg_index) asm_arm_str_reg_reg_reg((as), (reg_val), (reg_base), (reg_index))
 
+#define ASM_CLR_REG(as, reg_dest) asm_arm_eor_reg_reg_reg((as), (reg_dest), (reg_dest), (reg_dest))
+
 #endif // GENERIC_ASM_API
 
 #endif // MICROPY_INCLUDED_PY_ASMARM_H
diff --git a/py/asmrv32.h b/py/asmrv32.h
index 6f709daa11..1100d09801 100644
--- a/py/asmrv32.h
+++ b/py/asmrv32.h
@@ -804,7 +804,7 @@ void asm_rv32_emit_store_reg_reg_offset(asm_rv32_t *state, mp_uint_t source, mp_
 #define ASM_STORE32_REG_REG_OFFSET(state, rd, rs, offset) asm_rv32_emit_store_reg_reg_offset(state, rd, rs, offset, 2)
 #define ASM_SUB_REG_REG(state, rd, rs) asm_rv32_opcode_sub(state, rd, rd, rs)
 #define ASM_XOR_REG_REG(state, rd, rs) asm_rv32_emit_optimised_xor(state, rd, rs)
-#define ASM_CLR_REG(state, rd)
+#define ASM_CLR_REG(state, rd) asm_rv32_emit_optimised_xor(state, rd, rd)
 #define ASM_LOAD8_REG_REG_REG(state, rd, rs1, rs2) asm_rv32_emit_load_reg_reg_reg(state, rd, rs1, rs2, 0)
 #define ASM_LOAD16_REG_REG_REG(state, rd, rs1, rs2) asm_rv32_emit_load_reg_reg_reg(state, rd, rs1, rs2, 1)
 #define ASM_LOAD32_REG_REG_REG(state, rd, rs1, rs2) asm_rv32_emit_load_reg_reg_reg(state, rd, rs1, rs2, 2)
diff --git a/py/asmthumb.h b/py/asmthumb.h
index 5edf6573e1..88f4e399bc 100644
--- a/py/asmthumb.h
+++ b/py/asmthumb.h
@@ -485,6 +485,8 @@ void asm_thumb_b_rel12(asm_thumb_t *as, int rel);
         asm_thumb_str_rlo_rlo_rlo((as), (reg_val), (reg_base), (reg_index)); \
     } while (0)
 
+#define ASM_CLR_REG(as, reg_dest) asm_thumb_mov_rlo_i8((as), (reg_dest), 0)
+
 #endif // GENERIC_ASM_API
 
 #endif // MICROPY_INCLUDED_PY_ASMTHUMB_H
diff --git a/py/asmx64.h b/py/asmx64.h
index d80c5dcc13..efc3027b17 100644
--- a/py/asmx64.h
+++ b/py/asmx64.h
@@ -221,6 +221,8 @@ void asm_x64_call_ind(asm_x64_t *as, size_t fun_id, int temp_r32);
 #define ASM_STORE32_REG_REG(as, reg_src, reg_base) ASM_STORE32_REG_REG_OFFSET((as), (reg_src), (reg_base), 0)
 #define ASM_STORE32_REG_REG_OFFSET(as, reg_src, reg_base, dword_offset) asm_x64_mov_r32_to_mem32((as), (reg_src), (reg_base), 4 * (dword_offset))
 
+#define ASM_CLR_REG(as, reg_dest) asm_x64_xor_r64_r64((as), (reg_dest), (reg_dest))
+
 #endif // GENERIC_ASM_API
 
 #endif // MICROPY_INCLUDED_PY_ASMX64_H
diff --git a/py/asmx86.h b/py/asmx86.h
index d2e078ad51..80a67794d2 100644
--- a/py/asmx86.h
+++ b/py/asmx86.h
@@ -216,6 +216,8 @@ void asm_x86_call_ind(asm_x86_t *as, size_t fun_id, mp_uint_t n_args, int temp_r
 #define ASM_STORE32_REG_REG(as, reg_src, reg_base) ASM_STORE32_REG_REG_OFFSET((as), (reg_src), (reg_base), 0)
 #define ASM_STORE32_REG_REG_OFFSET(as, reg_src, reg_base, dword_offset) asm_x86_mov_r32_to_mem32((as), (reg_src), (reg_base), 4 * (dword_offset))
 
+#define ASM_CLR_REG(as, reg_dest) asm_x86_xor_r32_r32((as), (reg_dest), (reg_dest))
+
 #endif // GENERIC_ASM_API
 
 #endif // MICROPY_INCLUDED_PY_ASMX86_H
diff --git a/py/asmxtensa.h b/py/asmxtensa.h
index 559b3cacd5..15f8b4d92e 100644
--- a/py/asmxtensa.h
+++ b/py/asmxtensa.h
@@ -464,6 +464,8 @@ void asm_xtensa_l32r(asm_xtensa_t *as, mp_uint_t reg, mp_uint_t label);
         asm_xtensa_op_s32i_n((as), (reg_val), (reg_base), 0); \
     } while (0)
 
+#define ASM_CLR_REG(as, reg_dest) asm_xtensa_op_movi_n((as), (reg_dest), 0)
+
 #endif // GENERIC_ASM_API
 
 #endif // MICROPY_INCLUDED_PY_ASMXTENSA_H
diff --git a/py/emitnative.c b/py/emitnative.c
index a33ec01ec0..6cf01dcab1 100644
--- a/py/emitnative.c
+++ b/py/emitnative.c
@@ -282,17 +282,13 @@ struct _emit_t {
     ASM_T *as;
 };
 
-#ifndef REG_ZERO
-#define REG_ZERO REG_TEMP0
-#define ASM_CLR_REG(state, rd) ASM_XOR_REG_REG(state, rd, rd)
-#endif
-
-#if N_RV32
+#ifdef REG_ZERO
 #define ASM_MOV_LOCAL_MP_OBJ_NULL(as, local_num, reg_temp) \
     ASM_MOV_LOCAL_REG(as, local_num, REG_ZERO)
 #else
+#define REG_ZERO REG_TEMP0
 #define ASM_MOV_LOCAL_MP_OBJ_NULL(as, local_num, reg_temp) \
-    ASM_MOV_REG_IMM(as, reg_temp, (mp_uint_t)MP_OBJ_NULL); \
+    ASM_CLR_REG(as, reg_temp); \
     ASM_MOV_LOCAL_REG(as, local_num, reg_temp)
 #endif
 
@@ -1145,7 +1141,7 @@ static void emit_native_leave_exc_stack(emit_t *emit, bool start_of_handler) {
             // Optimisation: PC is already cleared by global exc handler
             return;
         }
-        ASM_XOR_REG_REG(emit->as, REG_RET, REG_RET);
+        ASM_CLR_REG(emit->as, REG_RET);
     } else {
         // Found new active handler, get its PC
         ASM_MOV_REG_PCREL(emit->as, REG_RET, e->label);
@@ -1242,8 +1238,7 @@ static void emit_native_global_exc_entry(emit_t *emit) {
             ASM_JUMP_IF_REG_ZERO(emit->as, REG_RET, start_label, true);
         } else {
             // Clear the unwind state
-            ASM_CLR_REG(emit->as, REG_ZERO);
-            ASM_MOV_LOCAL_REG(emit->as, LOCAL_IDX_EXC_HANDLER_UNWIND(emit), REG_ZERO);
+            ASM_MOV_LOCAL_MP_OBJ_NULL(emit->as, LOCAL_IDX_EXC_HANDLER_UNWIND(emit), REG_ZERO);
 
             // clear nlr.ret_val, because it's passed to mp_native_raise regardless
             // of whether there was an exception or not
@@ -1263,8 +1258,7 @@ static void emit_native_global_exc_entry(emit_t *emit) {
             ASM_JUMP_IF_REG_NONZERO(emit->as, REG_RET, global_except_label, true);
 
             // Clear PC of current code block, and jump there to resume execution
-            ASM_CLR_REG(emit->as, REG_ZERO);
-            ASM_MOV_LOCAL_REG(emit->as, LOCAL_IDX_EXC_HANDLER_PC(emit), REG_ZERO);
+            ASM_MOV_LOCAL_MP_OBJ_NULL(emit->as, LOCAL_IDX_EXC_HANDLER_PC(emit), REG_ZERO);
             ASM_JUMP_REG(emit->as, REG_LOCAL_1);
 
             // Global exception handler: check for valid exception handler
@@ -1945,7 +1939,7 @@ static void emit_native_delete_attr(emit_t *emit, qstr qst) {
     vtype_kind_t vtype_base;
     emit_pre_pop_reg(emit, &vtype_base, REG_ARG_1); // arg1 = base
     assert(vtype_base == VTYPE_PYOBJ);
-    ASM_XOR_REG_REG(emit->as, REG_ARG_3, REG_ARG_3); // arg3 = value (null for delete)
+    ASM_CLR_REG(emit->as, REG_ARG_3); // arg3 = value (null for delete)
     emit_call_with_qstr_arg(emit, MP_F_STORE_ATTR, qst, REG_ARG_2); // arg2 = attribute name
     emit_post(emit);
 }
@@ -2091,7 +2085,7 @@ static void emit_native_unwind_jump(emit_t *emit, mp_uint_t label, mp_uint_t exc
             // No finally, handle the jump ourselves
             // First, restore the exception handler address for the jump
             if (e < emit->exc_stack) {
-                ASM_XOR_REG_REG(emit->as, REG_RET, REG_RET);
+                ASM_CLR_REG(emit->as, REG_RET);
             } else {
                 ASM_MOV_REG_PCREL(emit->as, REG_RET, e->label);
             }
diff --git a/py/emitndebug.c b/py/emitndebug.c
index e49c5cdbff..2144d14e6b 100644
--- a/py/emitndebug.c
+++ b/py/emitndebug.c
@@ -271,6 +271,9 @@ static void asm_debug_setcc_reg_reg_reg(asm_debug_t *as, int op, int reg1, int r
 #define ASM_STORE32_REG_REG(as, reg_src, reg_base) \
     asm_debug_reg_reg(as, "store32", reg_src, reg_base)
 
+#define ASM_CLR_REG(as, reg_dest) \
+    asm_debug_reg(as, "clr", reg_dest)
+
 // Word indices of REG_LOCAL_x in nlr_buf_t
 #define NLR_BUF_IDX_LOCAL_1 (5) // rbx