diff options
| author | Jim Mussared | 2019-10-09 22:59:35 +1100 |
|---|---|---|
| committer | Damien George | 2019-10-10 17:39:32 +1100 |
| commit | 580a2656d10cc7c1fc93e094d7eb71f04d99c329 (patch) | |
| tree | d90ef3d7eeae092414b9de089522088e9fcd2deb | |
| parent | 305f537bf940fbbe3474cd1e0938586426d25b48 (diff) | |
stm32: Use hardware double sqrt on F7/H7 MCUs.
Identical to cd527bb324ade952d11a134859d38bf5272c165e but for doubles.
This gives a -2.754% improvement on bm_float.py, and -35% improvement on
calling sqrt in a loop.
| -rw-r--r-- | lib/libm_dbl/thumb_vfp_sqrt.c | 10 | ||||
| -rw-r--r-- | ports/stm32/Makefile | 6 |
2 files changed, 15 insertions, 1 deletions
diff --git a/lib/libm_dbl/thumb_vfp_sqrt.c b/lib/libm_dbl/thumb_vfp_sqrt.c new file mode 100644 index 000000000..dd37a07b0 --- /dev/null +++ b/lib/libm_dbl/thumb_vfp_sqrt.c @@ -0,0 +1,10 @@ +// an implementation of sqrt for Thumb using hardware double-precision VFP instructions + +double sqrt(double x) { + double ret; + asm volatile ( + "vsqrt.f64 %P0, %P1\n" + : "=w" (ret) + : "w" (x)); + return ret; +} diff --git a/ports/stm32/Makefile b/ports/stm32/Makefile index 1a4e3c690..28b90199a 100644 --- a/ports/stm32/Makefile +++ b/ports/stm32/Makefile @@ -173,12 +173,16 @@ SRC_LIBM = $(addprefix lib/libm_dbl/,\ scalbn.c \ sin.c \ sinh.c \ - sqrt.c \ tan.c \ tanh.c \ tgamma.c \ trunc.c \ ) +ifeq ($(MCU_SERIES),$(filter $(MCU_SERIES),f7 h7)) +SRC_LIBM += lib/libm_dbl/thumb_vfp_sqrt.c +else +SRC_LIBM += lib/libm_dbl/sqrt.c +endif else SRC_LIBM = $(addprefix lib/libm/,\ math.c \ |