diff --git a/py/nlrthumb.S b/py/nlrthumb.S
deleted file mode 100644
index 624275e8edfe22ac6ab2e4bf826fb1a5722254bc..0000000000000000000000000000000000000000
--- a/py/nlrthumb.S
+++ /dev/null
@@ -1,165 +0,0 @@
-/*
- * This file is part of the MicroPython project, http://micropython.org/
- *
- * The MIT License (MIT)
- *
- * Copyright (c) 2013-2015 Damien P. George
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
-#if (!defined(MICROPY_NLR_SETJMP) || !MICROPY_NLR_SETJMP) && (defined(__thumb2__) || defined(__thumb__) || defined(__arm__))
-
-// We only need the functions here if we are on arm/thumb, and we are not
-// using setjmp/longjmp.
-//
-// For reference, arm/thumb callee save regs are:
-// r4-r11, r13=sp
-
-// the offset of nlr_top within mp_state_ctx_t
-#define NLR_TOP_OFFSET (2 * 4)
-
- .syntax unified
- /*.cpu cortex-m4*/
- /*.thumb*/
- .text
- .align 2
-
-/**************************************/
-// mp_uint_t nlr_push(r0=nlr_buf_t *nlr)
-
- .global nlr_push
-#if defined(__thumb2__)
- .thumb
- .thumb_func
-#endif
- .type nlr_push, %function
-nlr_push:
- str r4, [r0, #12] @ store r4 into nlr_buf
- str r5, [r0, #16] @ store r5 into nlr_buf
- str r6, [r0, #20] @ store r6 into nlr_buf
- str r7, [r0, #24] @ store r7 into nlr_buf
-
-#if defined(__ARM_ARCH_6M__)
- mov r1, r8
- str r1, [r0, #28] @ store r8 into nlr_buf
- mov r1, r9
- str r1, [r0, #32] @ store r9 into nlr_buf
- mov r1, r10
- str r1, [r0, #36] @ store r10 into nlr_buf
- mov r1, r11
- str r1, [r0, #40] @ store r11 into nlr_buf
- mov r1, r13
- str r1, [r0, #44] @ store r13=sp into nlr_buf
- mov r1, lr
- str r1, [r0, #8] @ store lr into nlr_buf
-#else
- str r8, [r0, #28] @ store r8 into nlr_buf
- str r9, [r0, #32] @ store r9 into nlr_buf
- str r10, [r0, #36] @ store r10 into nlr_buf
- str r11, [r0, #40] @ store r11 into nlr_buf
- str r13, [r0, #44] @ store r13=sp into nlr_buf
- str lr, [r0, #8] @ store lr into nlr_buf
-#endif
-
- ldr r3, nlr_top_addr @ load addr of nlr_top
- ldr r2, [r3] @ load nlr_top
- str r2, [r0] @ store nlr_top into nlr_buf
- str r0, [r3] @ store nlr_buf into nlr_top (to link list)
-
- movs r0, #0 @ return 0, normal return
- bx lr @ return
- .size nlr_push, .-nlr_push
-
-/**************************************/
-// void nlr_pop()
-
- .global nlr_pop
-#if defined(__thumb2__)
- .thumb
- .thumb_func
-#endif
- .type nlr_pop, %function
-nlr_pop:
- ldr r3, nlr_top_addr @ load addr of nlr_top
- ldr r2, [r3] @ load nlr_top
- ldr r2, [r2] @ load prev nlr_buf
- str r2, [r3] @ store prev nlr_buf to nlr_top (to unlink list)
- bx lr @ return
- .size nlr_pop, .-nlr_pop
-
-/**************************************/
-// void nlr_jump(r0=mp_uint_t val)
-
- .global nlr_jump
-#if defined(__thumb2__)
- .thumb
- .thumb_func
-#endif
- .type nlr_jump, %function
-nlr_jump:
- ldr r3, nlr_top_addr @ load addr of nlr_top
- ldr r2, [r3] @ load nlr_top
- cmp r2, #0 @ test if nlr_top is NULL
-#if defined(__ARM_ARCH_6M__)
- bne nlr_jump_non_null @ if nlr_top is NULL, transfer control to nlr_jump_fail
- bl nlr_jump_fail
-nlr_jump_non_null:
-#else
- beq nlr_jump_fail @ if nlr_top is NULL, transfer control to nlr_jump_fail
-#endif
- str r0, [r2, #4] @ store return value
- ldr r0, [r2] @ load prev nlr_buf
- str r0, [r3] @ store prev nol_buf into nlr_top (to unlink list)
-
- ldr r4, [r2, #12] @ load r4 from nlr_buf
- ldr r5, [r2, #16] @ load r5 from nlr_buf
- ldr r6, [r2, #20] @ load r6 from nlr_buf
- ldr r7, [r2, #24] @ load r7 from nlr_buf
-#if defined(__ARM_ARCH_6M__)
- ldr r1, [r2, #28] @ load r8 from nlr_buf
- mov r8, r1
- ldr r1, [r2, #32] @ load r9 from nlr_buf
- mov r9, r1
- ldr r1, [r2, #36] @ load r10 from nlr_buf
- mov r10, r1
- ldr r1, [r2, #40] @ load r11 from nlr_buf
- mov r11, r1
- ldr r1, [r2, #44] @ load r13=sp from nlr_buf
- mov r13, r1
- ldr r1, [r2, #8] @ load lr from nlr_buf
- mov lr, r1
-#else
- ldr r8, [r2, #28] @ load r8 from nlr_buf
- ldr r9, [r2, #32] @ load r9 from nlr_buf
- ldr r10, [r2, #36] @ load r10 from nlr_buf
- ldr r11, [r2, #40] @ load r11 from nlr_buf
- ldr r13, [r2, #44] @ load r13=sp from nlr_buf
- ldr lr, [r2, #8] @ load lr from nlr_buf
-#endif
-
- movs r0, #1 @ return 1, non-local return
- bx lr @ return
- .size nlr_jump, .-nlr_jump
-
- .align 2
-nlr_top_addr:
- .word mp_state_ctx + NLR_TOP_OFFSET
-
-#endif // (!defined(MICROPY_NLR_SETJMP) || !MICROPY_NLR_SETJMP) && (defined(__thumb2__) || defined(__thumb__) || defined(__arm__))
diff --git a/py/nlrthumb.c b/py/nlrthumb.c
new file mode 100644
index 0000000000000000000000000000000000000000..a61c73c036c6f97f0062e8d527f6cb2aaa8c8b84
--- /dev/null
+++ b/py/nlrthumb.c
@@ -0,0 +1,134 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2013-2016 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/mpstate.h"
+#include "py/nlr.h"
+
+#if (!defined(MICROPY_NLR_SETJMP) || !MICROPY_NLR_SETJMP) && (defined(__thumb2__) || defined(__thumb__) || defined(__arm__))
+
+// We only need the functions here if we are on arm/thumb, and we are not
+// using setjmp/longjmp.
+//
+// For reference, arm/thumb callee save regs are:
+// r4-r11, r13=sp
+
+__attribute__((naked)) unsigned int nlr_push(nlr_buf_t *nlr) {
+
+ __asm volatile (
+ "str r4, [r0, #12] \n" // store r4 into nlr_buf
+ "str r5, [r0, #16] \n" // store r5 into nlr_buf
+ "str r6, [r0, #20] \n" // store r6 into nlr_buf
+ "str r7, [r0, #24] \n" // store r7 into nlr_buf
+
+#if defined(__ARM_ARCH_6M__)
+ "mov r1, r8 \n"
+ "str r1, [r0, #28] \n" // store r8 into nlr_buf
+ "mov r1, r9 \n"
+ "str r1, [r0, #32] \n" // store r9 into nlr_buf
+ "mov r1, r10 \n"
+ "str r1, [r0, #36] \n" // store r10 into nlr_buf
+ "mov r1, r11 \n"
+ "str r1, [r0, #40] \n" // store r11 into nlr_buf
+ "mov r1, r13 \n"
+ "str r1, [r0, #44] \n" // store r13=sp into nlr_buf
+ "mov r1, lr \n"
+ "str r1, [r0, #8] \n" // store lr into nlr_buf
+#else
+ "str r8, [r0, #28] \n" // store r8 into nlr_buf
+ "str r9, [r0, #32] \n" // store r9 into nlr_buf
+ "str r10, [r0, #36] \n" // store r10 into nlr_buf
+ "str r11, [r0, #40] \n" // store r11 into nlr_buf
+ "str r13, [r0, #44] \n" // store r13=sp into nlr_buf
+ "str lr, [r0, #8] \n" // store lr into nlr_buf
+#endif
+
+ "b nlr_push_tail \n" // do the rest in C
+ );
+
+ return 0; // needed to silence compiler warning
+}
+
+unsigned int nlr_push_tail(nlr_buf_t *nlr) {
+ nlr_buf_t **top = &MP_STATE_THREAD(nlr_top);
+ nlr->prev = *top;
+ *top = nlr;
+ return 0; // normal return
+}
+
+void nlr_pop(void) {
+ nlr_buf_t **top = &MP_STATE_THREAD(nlr_top);
+ *top = (*top)->prev;
+}
+
+NORETURN __attribute__((naked)) void nlr_jump(void *val) {
+ nlr_buf_t **top_ptr = &MP_STATE_THREAD(nlr_top);
+ nlr_buf_t *top = *top_ptr;
+ if (top == NULL) {
+ nlr_jump_fail(val);
+ }
+
+ top->ret_val = val;
+ *top_ptr = top->prev;
+
+ __asm volatile (
+ "mov r0, %0 \n" // r0 points to nlr_buf
+ "ldr r4, [r0, #12] \n" // load r4 from nlr_buf
+ "ldr r5, [r0, #16] \n" // load r5 from nlr_buf
+ "ldr r6, [r0, #20] \n" // load r6 from nlr_buf
+ "ldr r7, [r0, #24] \n" // load r7 from nlr_buf
+
+#if defined(__ARM_ARCH_6M__)
+ "ldr r1, [r0, #28] \n" // load r8 from nlr_buf
+ "mov r8, r1 \n"
+ "ldr r1, [r0, #32] \n" // load r9 from nlr_buf
+ "mov r9, r1 \n"
+ "ldr r1, [r0, #36] \n" // load r10 from nlr_buf
+ "mov r10, r1 \n"
+ "ldr r1, [r0, #40] \n" // load r11 from nlr_buf
+ "mov r11, r1 \n"
+ "ldr r1, [r0, #44] \n" // load r13=sp from nlr_buf
+ "mov r13, r1 \n"
+ "ldr r1, [r0, #8] \n" // load lr from nlr_buf
+ "mov lr, r1 \n"
+#else
+ "ldr r8, [r0, #28] \n" // load r8 from nlr_buf
+ "ldr r9, [r0, #32] \n" // load r9 from nlr_buf
+ "ldr r10, [r0, #36] \n" // load r10 from nlr_buf
+ "ldr r11, [r0, #40] \n" // load r11 from nlr_buf
+ "ldr r13, [r0, #44] \n" // load r13=sp from nlr_buf
+ "ldr lr, [r0, #8] \n" // load lr from nlr_buf
+#endif
+ "movs r0, #1 \n" // return 1, non-local return
+ "bx lr \n" // return
+ : // output operands
+ : "r"(top) // input operands
+ : // clobbered registers
+ );
+
+ for (;;); // needed to silence compiler warning
+}
+
+#endif // (!defined(MICROPY_NLR_SETJMP) || !MICROPY_NLR_SETJMP) && (defined(__thumb2__) || defined(__thumb__) || defined(__arm__))