1 files changed, 74 insertions, 0 deletions
diff --git a/py/nlr.c b/py/nlr.c
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index 000000000..e4d6d10c0
--- /dev/null
+++ b/py/nlr.c
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+/*
+ * 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"
+
+// Helper macros to save/restore the pystack state
+#if MICROPY_ENABLE_PYSTACK
+#define MP_NLR_SAVE_PYSTACK(nlr_buf) (nlr_buf)->pystack = MP_STATE_THREAD(pystack_cur)
+#define MP_NLR_RESTORE_PYSTACK(nlr_buf) MP_STATE_THREAD(pystack_cur) = (nlr_buf)->pystack
+#else
+#define MP_NLR_SAVE_PYSTACK(nlr_buf) (void)nlr_buf
+#define MP_NLR_RESTORE_PYSTACK(nlr_buf) (void)nlr_buf
+#endif
+
+#if !MICROPY_NLR_SETJMP
+// When not using setjmp, nlr_push_tail is called from inline asm so needs special care
+#if MICROPY_NLR_X86 && (defined(_WIN32) || defined(__CYGWIN__))
+// On these 32-bit platforms make sure nlr_push_tail doesn't have a leading underscore
+unsigned int nlr_push_tail(nlr_buf_t *nlr) asm("nlr_push_tail");
+#else
+// LTO can't see inside inline asm functions so explicitly mark nlr_push_tail as used
+__attribute__((used)) unsigned int nlr_push_tail(nlr_buf_t *nlr);
+#endif
+#endif
+
+unsigned int nlr_push_tail(nlr_buf_t *nlr) {
+    nlr_buf_t **top = &MP_STATE_THREAD(nlr_top);
+    nlr->prev = *top;
+    MP_NLR_SAVE_PYSTACK(nlr);
+    *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;
+    MP_NLR_RESTORE_PYSTACK(top);
+    *top_ptr = top->prev;
+
+    nlr_jump_tail(top);
+}