circuitpython/py/nlrthumb.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"
#if MICROPY_NLR_THUMB
#undef nlr_push
// 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
#if defined(__ARM_ARCH_6M__)
"ldr r1, nlr_push_tail_var \n"
"bx r1 \n" // do the rest in C
".align 2 \n"
"nlr_push_tail_var: .word nlr_push_tail \n"
#else
"b nlr_push_tail \n" // do the rest in C
#endif
: // output operands
: "r" (nlr) // input operands
// Do not use r1, r2, r3 as temporary saving registers.
// gcc 7.2.1 started doing this, and r3 got clobbered in nlr_push_tail.
// See https://github.com/adafruit/circuitpython/issues/500 for details.
: "r1", "r2", "r3" // clobbers
);
#if !defined(__clang__) && defined(__GNUC__) && (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 8))
// Older versions of gcc give an error when naked functions don't return a value
// Additionally exclude Clang as it also defines __GNUC__ but doesn't need this statement
return 0;
#endif
}
NORETURN void nlr_jump(void *val) {
MP_NLR_JUMP_HEAD(val, top)
__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
);
MP_UNREACHABLE
}
#endif // MICROPY_NLR_THUMB