py/nlrx86: Convert from assembler to C file with inline asm.
diff --git a/py/nlrx86.c b/py/nlrx86.c
new file mode 100644
index 0000000..4b178f4
--- /dev/null
+++ b/py/nlrx86.c
@@ -0,0 +1,106 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2013-2017 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 !MICROPY_NLR_SETJMP && defined(__i386__)
+
+#undef nlr_push
+
+// For reference, x86 callee save regs are:
+//  ebx, esi, edi, ebp, esp, eip
+
+#define NLR_OS_WINDOWS (defined(_WIN32) || defined(__CYGWIN__))
+
+#if NLR_OS_WINDOWS
+unsigned int nlr_push_tail(nlr_buf_t *nlr) asm("nlr_push_tail");
+#else
+__attribute__((used)) unsigned int nlr_push_tail(nlr_buf_t *nlr);
+#endif
+
+unsigned int nlr_push(nlr_buf_t *nlr) {
+    (void)nlr;
+
+    __asm volatile (
+    "pop    %ebp                \n" // undo function's prelude
+    "mov    4(%esp), %edx       \n" // load nlr_buf
+    "mov    (%esp), %eax        \n" // load return %eip
+    "mov    %eax, 8(%edx)       \n" // store %eip into nlr_buf
+    "mov    %ebp, 12(%edx)      \n" // store %ebp into nlr_buf
+    "mov    %esp, 16(%edx)      \n" // store %esp into nlr_buf
+    "mov    %ebx, 20(%edx)      \n" // store %ebx into nlr_buf
+    "mov    %edi, 24(%edx)      \n" // store %edi into nlr_buf
+    "mov    %esi, 28(%edx)      \n" // store %esi into nlr_buf
+    "jmp    nlr_push_tail       \n" // do the rest in C
+    );
+
+    return 0; // needed to silence compiler warning
+}
+
+__attribute__((used)) 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 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    %0, %%edx           \n" // %edx points to nlr_buf
+    "mov    28(%%edx), %%esi    \n" // load saved %esi
+    "mov    24(%%edx), %%edi    \n" // load saved %edi
+    "mov    20(%%edx), %%ebx    \n" // load saved %ebx
+    "mov    16(%%edx), %%esp    \n" // load saved %esp
+    "mov    12(%%edx), %%ebp    \n" // load saved %ebp
+    "mov    8(%%edx), %%eax     \n" // load saved %eip
+    "mov    %%eax, (%%esp)      \n" // store saved %eip to stack
+    "xor    %%eax, %%eax        \n" // clear return register
+    "inc    %%al                \n" // increase to make 1, non-local return
+    "ret                        \n" // return
+    :                               // output operands
+    : "r"(top)                      // input operands
+    :                               // clobbered registers
+    );
+
+    for (;;); // needed to silence compiler warning
+}
+
+#endif // !MICROPY_NLR_SETJMP && defined(__i386__)