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py/nlr: Factor out common NLR code to macro and generic funcs in nlr.c.
Each NLR implementation (Thumb, x86, x64, xtensa, setjmp) duplicates a lot of the NLR code, specifically that dealing with pushing and popping the NLR pointer to maintain the linked-list of NLR buffers. This patch factors all of that code out of the specific implementations into generic functions in nlr.c, along with a helper macro in nlr.h. This eliminates duplicated code.
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8 files changed

Lines changed: 76 additions & 103 deletions

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‎py/nlr.c‎

Lines changed: 51 additions & 0 deletions
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/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2013-2017 Damien P. George
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "py/mpstate.h"
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#if !MICROPY_NLR_SETJMP
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// When not using setjmp, nlr_push_tail is called from inline asm so needs special c
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#if MICROPY_NLR_X86 && (defined(_WIN32) || defined(__CYGWIN__))
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// On these 32-bit platforms make sure nlr_push_tail doesn't have a leading undersco
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unsigned int nlr_push_tail(nlr_buf_t *nlr) asm("nlr_push_tail");
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#else
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// LTO can't see inside inline asm functions so explicitly mark nlr_push_tail as use
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__attribute__((used)) unsigned int nlr_push_tail(nlr_buf_t *nlr);
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#endif
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#endif
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unsigned int nlr_push_tail(nlr_buf_t *nlr) {
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nlr_buf_t **top = &MP_STATE_THREAD(nlr_top);
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nlr->prev = *top;
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MP_NLR_SAVE_PYSTACK(nlr);
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*top = nlr;
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return 0; // normal return
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}
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void nlr_pop(void) {
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nlr_buf_t **top = &MP_STATE_THREAD(nlr_top);
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*top = (*top)->prev;
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}

‎py/nlr.h‎

Lines changed: 16 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -88,24 +88,29 @@ struct _nlr_buf_t {
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#define MP_NLR_RESTORE_PYSTACK(nlr_buf) (void)nlr_buf
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#endif
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91-
#if MICROPY_NLR_SETJMP
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#include "py/mpstate.h"
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// Helper macro to use at the start of a specific nlr_jump implementation
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#define MP_NLR_JUMP_HEAD(val, top) \
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nlr_buf_t **_top_ptr = &MP_STATE_THREAD(nlr_top); \
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nlr_buf_t *top = *_top_ptr; \
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if (top == NULL) { \
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nlr_jump_fail(val); \
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} \
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top->ret_val = val; \
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MP_NLR_RESTORE_PYSTACK(top); \
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*_top_ptr = top->prev; \
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94-
NORETURN void nlr_setjmp_jump(void *val);
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#if MICROPY_NLR_SETJMP
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// nlr_push() must be defined as a macro, because "The stack context will be
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// invalidated if the function which called setjmp() returns."
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#define nlr_push(buf) ( \
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(buf)->prev = MP_STATE_THREAD(nlr_top), \
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MP_NLR_SAVE_PYSTACK(buf), \
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MP_STATE_THREAD(nlr_top) = (buf), \
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setjmp((buf)->jmpbuf))
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#define nlr_pop() { MP_STATE_THREAD(nlr_top) = MP_STATE_THREAD(nlr_top)->prev; }
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#define nlr_jump(val) nlr_setjmp_jump(val)
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// For this case it is safe to call nlr_push_tail() first.
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#define nlr_push(buf) (nlr_push_tail(buf), setjmp((buf)->jmpbuf))
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#else
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unsigned int nlr_push(nlr_buf_t *);
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#endif
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unsigned int nlr_push_tail(nlr_buf_t *top);
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void nlr_pop(void);
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NORETURN void nlr_jump(void *val);
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#endif
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// This must be implemented by a port. It's called by nlr_jump
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// if no nlr buf has been pushed. It must not return, but rather

‎py/nlrsetjmp.c‎

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@@ -3,7 +3,7 @@
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2013, 2014 Damien P. George
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* Copyright (c) 2013-2017 Damien P. George
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* THE SOFTWARE.
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*/
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27-
#include "py/nlr.h"
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#include "py/mpstate.h"
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#if MICROPY_NLR_SETJMP
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void nlr_setjmp_jump(void *val) {
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void nlr_jump(void *val) {
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nlr_buf_t **top_ptr = &MP_STATE_THREAD(nlr_top);
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nlr_buf_t *top = *top_ptr;
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if (top == NULL) {

‎py/nlrthumb.c‎

Lines changed: 2 additions & 23 deletions
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@@ -3,7 +3,7 @@
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2013-2016 Damien P. George
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* Copyright (c) 2013-2017 Damien P. George
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
@@ -82,29 +82,8 @@ __attribute__((naked)) unsigned int nlr_push(nlr_buf_t *nlr) {
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#endif
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}
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85-
__attribute__((used)) unsigned int nlr_push_tail(nlr_buf_t *nlr) {
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nlr_buf_t **top = &MP_STATE_THREAD(nlr_top);
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nlr->prev = *top;
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MP_NLR_SAVE_PYSTACK(nlr);
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*top = nlr;
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return 0; // normal return
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}
92-
93-
void nlr_pop(void) {
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nlr_buf_t **top = &MP_STATE_THREAD(nlr_top);
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*top = (*top)->prev;
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}
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NORETURN void nlr_jump(void *val) {
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nlr_buf_t **top_ptr = &MP_STATE_THREAD(nlr_top);
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nlr_buf_t *top = *top_ptr;
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if (top == NULL) {
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nlr_jump_fail(val);
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}
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105-
top->ret_val = val;
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MP_NLR_RESTORE_PYSTACK(top);
107-
*top_ptr = top->prev;
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MP_NLR_JUMP_HEAD(val, top)
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10988
__asm volatile (
11089
"mov r0, %0 \n" // r0 points to nlr_buf

‎py/nlrx64.c‎

Lines changed: 1 addition & 22 deletions
Original file line numberDiff line numberDiff line change
@@ -88,29 +88,8 @@ unsigned int nlr_push(nlr_buf_t *nlr) {
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return 0; // needed to silence compiler warning
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}
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91-
__attribute__((used)) unsigned int nlr_push_tail(nlr_buf_t *nlr) {
92-
nlr_buf_t **top = &MP_STATE_THREAD(nlr_top);
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nlr->prev = *top;
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MP_NLR_SAVE_PYSTACK(nlr);
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*top = nlr;
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return 0; // normal return
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}
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99-
void nlr_pop(void) {
100-
nlr_buf_t **top = &MP_STATE_THREAD(nlr_top);
101-
*top = (*top)->prev;
102-
}
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NORETURN void nlr_jump(void *val) {
105-
nlr_buf_t **top_ptr = &MP_STATE_THREAD(nlr_top);
106-
nlr_buf_t *top = *top_ptr;
107-
if (top == NULL) {
108-
nlr_jump_fail(val);
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}
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111-
top->ret_val = val;
112-
MP_NLR_RESTORE_PYSTACK(top);
113-
*top_ptr = top->prev;
92+
MP_NLR_JUMP_HEAD(val, top)
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11594
__asm volatile (
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"movq %0, %%rcx \n" // %rcx points to nlr_buf

‎py/nlrx86.c‎

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Original file line numberDiff line numberDiff line change
@@ -70,29 +70,8 @@ unsigned int nlr_push(nlr_buf_t *nlr) {
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return 0; // needed to silence compiler warning
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}
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73-
__attribute__((used)) unsigned int nlr_push_tail(nlr_buf_t *nlr) {
74-
nlr_buf_t **top = &MP_STATE_THREAD(nlr_top);
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nlr->prev = *top;
76-
MP_NLR_SAVE_PYSTACK(nlr);
77-
*top = nlr;
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return 0; // normal return
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}
80-
81-
void nlr_pop(void) {
82-
nlr_buf_t **top = &MP_STATE_THREAD(nlr_top);
83-
*top = (*top)->prev;
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}
85-
8673
NORETURN void nlr_jump(void *val) {
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nlr_buf_t **top_ptr = &MP_STATE_THREAD(nlr_top);
88-
nlr_buf_t *top = *top_ptr;
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if (top == NULL) {
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nlr_jump_fail(val);
91-
}
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93-
top->ret_val = val;
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MP_NLR_RESTORE_PYSTACK(top);
95-
*top_ptr = top->prev;
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MP_NLR_JUMP_HEAD(val, top)
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9776
__asm volatile (
9877
"mov %0, %%edx \n" // %edx points to nlr_buf

‎py/nlrxtensa.c‎

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Original file line numberDiff line numberDiff line change
@@ -55,29 +55,8 @@ unsigned int nlr_push(nlr_buf_t *nlr) {
5555
return 0; // needed to silence compiler warning
5656
}
5757

58-
__attribute__((used)) unsigned int nlr_push_tail(nlr_buf_t *nlr) {
59-
nlr_buf_t **top = &MP_STATE_THREAD(nlr_top);
60-
nlr->prev = *top;
61-
MP_NLR_SAVE_PYSTACK(nlr);
62-
*top = nlr;
63-
return 0; // normal return
64-
}
65-
66-
void nlr_pop(void) {
67-
nlr_buf_t **top = &MP_STATE_THREAD(nlr_top);
68-
*top = (*top)->prev;
69-
}
70-
7158
NORETURN void nlr_jump(void *val) {
72-
nlr_buf_t **top_ptr = &MP_STATE_THREAD(nlr_top);
73-
nlr_buf_t *top = *top_ptr;
74-
if (top == NULL) {
75-
nlr_jump_fail(val);
76-
}
77-
78-
top->ret_val = val;
79-
MP_NLR_RESTORE_PYSTACK(top);
80-
*top_ptr = top->prev;
59+
MP_NLR_JUMP_HEAD(val, top)
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8261
__asm volatile (
8362
"mov.n a2, %0 \n" // a2 points to nlr_buf

‎py/py.mk‎

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@@ -103,6 +103,7 @@ endif
103103
# py object files
104104
PY_O_BASENAME = \
105105
mpstate.o \
106+
nlr.o \
106107
nlrx86.o \
107108
nlrx64.o \
108109
nlrthumb.o \

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