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py/nlrthumb: Save and restore VFP registers s16-s21 when CPU has them. 

These s16-s21 registers are used by gcc so need to be saved.  Future
versions of gcc (beyond v9.1.0), or other compilers, may eventually need
additional registers saved/restored.

See issue #4844.
This commit is contained in:
Damien George 2019-06-17 23:19:34 +10:00 committed by Scott Shawcroft
parent 1cf0ce094a
commit 767d47dd60
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GPG Key ID: 9349BC7E64B1921E
2 changed files with 18 additions and 1 deletions
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9
py/nlr.h
View File

@ -54,7 +54,14 @@
#endif
#elif defined(__thumb2__) || defined(__thumb__) || defined(__arm__)
#define MICROPY_NLR_THUMB (1)
#define MICROPY_NLR_NUM_REGS (10)
#if defined(__SOFTFP__)
#define MICROPY_NLR_NUM_REGS (10)
#else
// With hardware FP registers s16-s31 are callee save so in principle
// should be saved and restored by the NLR code. gcc only uses s16-s21
// so only save/restore those as an optimisation.
#define MICROPY_NLR_NUM_REGS (10 + 6)
#endif
#elif defined(__xtensa__)
#define MICROPY_NLR_XTENSA (1)
#define MICROPY_NLR_NUM_REGS (10)

10
py/nlrthumb.c
View File

@ -63,6 +63,11 @@ __attribute__((naked)) unsigned int nlr_push(nlr_buf_t *nlr) {
"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
#if MICROPY_NLR_NUM_REGS == 16
"vstr d8, [r0, #48] \n" // store s16-s17 into nlr_buf
"vstr d9, [r0, #56] \n" // store s18-s19 into nlr_buf
"vstr d10, [r0, #64] \n" // store s20-s21 into nlr_buf
#endif
"str lr, [r0, #8] \n" // store lr into nlr_buf
#endif
@ -118,6 +123,11 @@ NORETURN void nlr_jump(void *val) {
"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
#if MICROPY_NLR_NUM_REGS == 16
"vldr d8, [r0, #48] \n" // load s16-s17 from nlr_buf
"vldr d9, [r0, #56] \n" // load s18-s19 from nlr_buf
"vldr d10, [r0, #64] \n" // load s20-s21 from nlr_buf
#endif
"ldr lr, [r0, #8] \n" // load lr from nlr_buf
#endif
"movs r0, #1 \n" // return 1, non-local return