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pulseIn: add ASM implementation for Due

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This commit is contained in:
Martino Facchin 2015-05-29 14:19:54 +02:00
parent 7a22827359
commit bb3963c0e9
4 changed files with 185 additions and 25 deletions
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36
hardware/arduino/sam/cores/arduino/wiring_pulse.cpp
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@ -23,39 +23,27 @@
* or LOW, the type of pulse to measure. Works on pulses from 2-3 microseconds * or LOW, the type of pulse to measure. Works on pulses from 2-3 microseconds
* to 3 minutes in length, but must be called at least a few dozen microseconds * to 3 minutes in length, but must be called at least a few dozen microseconds
* before the start of the pulse. */ * before the start of the pulse. */
extern uint32_t pulseIn( uint32_t pin, uint32_t state, uint32_t timeout ) uint32_t pulseIn( uint32_t pin, uint32_t state, uint32_t timeout )
{ {
// cache the port and bit of the pin in order to speed up the // cache the port and bit of the pin in order to speed up the
// pulse width measuring loop and achieve finer resolution. calling // pulse width measuring loop and achieve finer resolution. calling
// digitalRead() instead yields much coarser resolution. // digitalRead() instead yields much coarser resolution.
PinDescription p = g_APinDescription[pin]; PinDescription p = g_APinDescription[pin];
uint32_t width = 0; // keep initialization out of time critical area uint32_t bit = p.ulPin;
uint32_t stateMask = state ? bit : 0;
// convert the timeout from microseconds to a number of times through // convert the timeout from microseconds to a number of times through
// the initial loop; it takes 22 clock cycles per iteration. // the initial loop; it takes (roughly) 18 clock cycles per iteration.
uint32_t numloops = 0; uint32_t maxloops = microsecondsToClockCycles(timeout) / 18;
uint32_t maxloops = microsecondsToClockCycles(timeout) / 22;
uint32_t width = countPulseASM(&(p.pPort->PIO_PDSR), bit, stateMask, maxloops);
// wait for any previous pulse to end
while (PIO_Get(p.pPort, PIO_INPUT, p.ulPin) == state)
if (numloops++ == maxloops)
return 0;
// wait for the pulse to start
while (PIO_Get(p.pPort, PIO_INPUT, p.ulPin) != state)
if (numloops++ == maxloops)
return 0;
// wait for the pulse to stop
while (PIO_Get(p.pPort, PIO_INPUT, p.ulPin) == state) {
if (numloops++ == maxloops)
return 0;
width++;
}
// convert the reading to microseconds. The loop has been determined // convert the reading to microseconds. The loop has been determined
// to be 52 clock cycles long and have about 16 clocks between the edge // to be 18 clock cycles long and have about 16 clocks between the edge
// and the start of the loop. There will be some error introduced by // and the start of the loop. There will be some error introduced by
// the interrupt handlers. // the interrupt handlers.
return clockCyclesToMicroseconds(width * 52 + 16); if (width)
return clockCyclesToMicroseconds(width * 18 + 16);
else
return 0;
} }

1
hardware/arduino/sam/cores/arduino/wiring_pulse.h
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@ -23,6 +23,7 @@
extern "C" { extern "C" {
#endif #endif
unsigned long countPulseASM(const volatile uint32_t *port, uint32_t bit, uint32_t stateMask, unsigned long maxloops);
/* /*
* \brief Measures the length (in microseconds) of a pulse on the pin; state is HIGH * \brief Measures the length (in microseconds) of a pulse on the pin; state is HIGH
* or LOW, the type of pulse to measure. Works on pulses from 2-3 microseconds * or LOW, the type of pulse to measure. Works on pulses from 2-3 microseconds

166
hardware/arduino/sam/cores/arduino/wiring_pulse_asm.S Normal file
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@ -0,0 +1,166 @@
/*
Copyright (c) 2015 Arduino LLC. All right reserved.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
/*
The following function has been compiled to ASM with gcc
unsigned long countPulseASM(const volatile uint32_t *port, uint32_t bit, uint32_t stateMask, unsigned long maxloops)
{
unsigned long width = 0;
// wait for any previous pulse to end
while ((*port & bit) == stateMask)
if (--maxloops == 0)
return 0;
// wait for the pulse to start
while ((*port & bit) != stateMask)
if (--maxloops == 0)
return 0;
// wait for the pulse to stop
while ((*port & bit) == stateMask) {
if (++width == maxloops)
return 0;
}
return width;
}
using the command line:
arm-none-eabi-gcc -mcpu=cortex-m3 -mthumb -c -O2 -W -ffunction-sections -fdata-sections -nostdlib \
countPulseASM.c -Wa,-ahlmsd=output.lst -dp -fverbose-asm -S \
-I.arduino15/packages/arduino/hardware/sam/1.6.3/cores/arduino \
-I.arduino15/packages/arduino/hardware/sam/1.6.3/system/CMSIS/CMSIS/Include \
-I.arduino15/packages/arduino/hardware/sam/1.6.3/system/CMSIS/Device/ATMEL \
-I.arduino15/packages/arduino/hardware/sam/1.6.3/system/libsam/include \
-I.arduino15/packages/arduino/hardware/sam/1.6.3/variants/arduino_due_x
The result has been slightly edited to increase readability.
*/
.syntax unified
.cpu cortex-m3
.fpu softvfp
.eabi_attribute 20, 1 @ Tag_ABI_FP_denormal
.eabi_attribute 21, 1 @ Tag_ABI_FP_exceptions
.eabi_attribute 23, 3 @ Tag_ABI_FP_number_model
.eabi_attribute 24, 1 @ Tag_ABI_align8_needed
.eabi_attribute 25, 1 @ Tag_ABI_align8_preserved
.eabi_attribute 26, 1 @ Tag_ABI_enum_size
.eabi_attribute 30, 2 @ Tag_ABI_optimization_goals
.eabi_attribute 34, 1 @ Tag_CPU_unaligned_access
.eabi_attribute 18, 4 @ Tag_ABI_PCS_wchar_t
.file "countPulseASM.c"
@ GNU C (GNU Tools for ARM Embedded Processors) version 4.9.3 20150303 (release) [ARM/embedded-4_9-branch revision 221220] (arm-none-eabi)
@ compiled by GNU C version 4.7.4, GMP version 4.3.2, MPFR version 2.4.2, MPC version 0.8.1
@ GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
@ options passed:
@ -I .arduino15/packages/arduino/hardware/sam/1.6.3/cores/arduino
@ -I .arduino15/packages/arduino/hardware/sam/1.6.3/system/CMSIS/CMSIS/Include
@ -I .arduino15/packages/arduino/hardware/sam/1.6.3/system/CMSIS/Device/ATMEL
@ -I .arduino15/packages/arduino/hardware/sam/1.6.3/system/libsam/include
@ -I .arduino15/packages/arduino/hardware/sam/1.6.3/variants/arduino_due_x
@ -imultilib armv7-m -iprefix /usr/bin/../lib/gcc/arm-none-eabi/4.9.3/
@ -isysroot /usr/bin/../arm-none-eabi -D__USES_INITFINI__ countPulseASM.c
@ -mcpu=cortex-m3 -mthumb -O2 -Wextra -ffunction-sections -fdata-sections
@ -fverbose-asm
@ options enabled: -faggressive-loop-optimizations -fauto-inc-dec
@ -fbranch-count-reg -fcaller-saves -fcombine-stack-adjustments -fcommon
@ -fcompare-elim -fcprop-registers -fcrossjumping -fcse-follow-jumps
@ -fdata-sections -fdefer-pop -fdelete-null-pointer-checks -fdevirtualize
@ -fdevirtualize-speculatively -fdwarf2-cfi-asm -fearly-inlining
@ -feliminate-unused-debug-types -fexpensive-optimizations
@ -fforward-propagate -ffunction-cse -ffunction-sections -fgcse -fgcse-lm
@ -fgnu-runtime -fgnu-unique -fguess-branch-probability
@ -fhoist-adjacent-loads -fident -fif-conversion -fif-conversion2
@ -findirect-inlining -finline -finline-atomics
@ -finline-functions-called-once -finline-small-functions -fipa-cp
@ -fipa-profile -fipa-pure-const -fipa-reference -fipa-sra
@ -fira-hoist-pressure -fira-share-save-slots -fira-share-spill-slots
@ -fisolate-erroneous-paths-dereference -fivopts -fkeep-static-consts
@ -fleading-underscore -flifetime-dse -fmath-errno -fmerge-constants
@ -fmerge-debug-strings -fmove-loop-invariants -fomit-frame-pointer
@ -foptimize-sibling-calls -foptimize-strlen -fpartial-inlining -fpeephole
@ -fpeephole2 -fprefetch-loop-arrays -freg-struct-return -freorder-blocks
@ -freorder-functions -frerun-cse-after-loop
@ -fsched-critical-path-heuristic -fsched-dep-count-heuristic
@ -fsched-group-heuristic -fsched-interblock -fsched-last-insn-heuristic
@ -fsched-pressure -fsched-rank-heuristic -fsched-spec
@ -fsched-spec-insn-heuristic -fsched-stalled-insns-dep -fschedule-insns
@ -fschedule-insns2 -fsection-anchors -fshow-column -fshrink-wrap
@ -fsigned-zeros -fsplit-ivs-in-unroller -fsplit-wide-types
@ -fstrict-aliasing -fstrict-overflow -fstrict-volatile-bitfields
@ -fsync-libcalls -fthread-jumps -ftoplevel-reorder -ftrapping-math
@ -ftree-bit-ccp -ftree-builtin-call-dce -ftree-ccp -ftree-ch
@ -ftree-coalesce-vars -ftree-copy-prop -ftree-copyrename -ftree-cselim
@ -ftree-dce -ftree-dominator-opts -ftree-dse -ftree-forwprop -ftree-fre
@ -ftree-loop-if-convert -ftree-loop-im -ftree-loop-ivcanon
@ -ftree-loop-optimize -ftree-parallelize-loops= -ftree-phiprop -ftree-pre
@ -ftree-pta -ftree-reassoc -ftree-scev-cprop -ftree-sink -ftree-slsr
@ -ftree-sra -ftree-switch-conversion -ftree-tail-merge -ftree-ter
@ -ftree-vrp -funit-at-a-time -fverbose-asm -fzero-initialized-in-bss
@ -mfix-cortex-m3-ldrd -mlittle-endian -mlra -mpic-data-is-text-relative
@ -msched-prolog -mthumb -munaligned-access -mvectorize-with-neon-quad
.section .text.countPulseASM,"ax",%progbits
.align 2
.global countPulseASM
.thumb
.thumb_func
.type countPulseASM, %function
countPulseASM:
@ args = 0, pretend = 0, frame = 0
@ frame_needed = 0, uses_anonymous_args = 0
@ link register save eliminated.
push {r4, r5} @ @ 132 *push_multi [length = 2]
b .L2 @ @ 178 *arm_jump [length = 2]
.L4:
subs r3, r3, #1 @ maxloops, maxloops, @ 18 thumb2_addsi3_compare0/1 [length = 2]
beq .L12 @, @ 19 arm_cond_branch [length = 2]
.L2:
ldr r4, [r0] @ D.4169, *port_7(D) @ 22 *thumb2_movsi_insn/6 [length = 4]
ands r4, r4, r1 @, D.4169, D.4169, bit @ 24 *thumb2_alusi3_short [length = 2]
cmp r4, r2 @ D.4169, stateMask @ 25 *arm_cmpsi_insn/2 [length = 2]
beq .L4 @, @ 26 arm_cond_branch [length = 2]
b .L6 @ @ 181 *arm_jump [length = 2]
.L7:
subs r3, r3, #1 @ maxloops, maxloops, @ 32 thumb2_addsi3_compare0/1 [length = 2]
beq .L12 @, @ 33 arm_cond_branch [length = 2]
.L6:
ldr r4, [r0] @ D.4169, *port_7(D) @ 41 *thumb2_movsi_insn/6 [length = 4]
ands r4, r4, r1 @, D.4169, D.4169, bit @ 43 *thumb2_alusi3_short [length = 2]
cmp r4, r2 @ D.4169, stateMask @ 44 *arm_cmpsi_insn/2 [length = 2]
bne .L7 @, @ 45 arm_cond_branch [length = 2]
movs r5, #0 @ width, @ 7 *thumb2_movsi_shortim [length = 2]
b .L9 @ @ 183 *arm_jump [length = 2]
.L10:
adds r5, r5, #1 @ width, width, @ 50 *thumb2_addsi_short/1 [length = 2]
cmp r3, r5 @ maxloops, width @ 51 *arm_cmpsi_insn/2 [length = 2]
beq .L22 @, @ 52 arm_cond_branch [length = 2]
.L9:
ldr r4, [r0] @ D.4169, *port_7(D) @ 60 *thumb2_movsi_insn/6 [length = 4]
ands r4, r4, r1 @, D.4169, D.4169, bit @ 62 *thumb2_alusi3_short [length = 2]
cmp r4, r2 @ D.4169, stateMask @ 63 *arm_cmpsi_insn/2 [length = 2]
beq .L10 @, @ 64 arm_cond_branch [length = 2]
mov r0, r5 @ D.4169, width @ 9 *thumb2_movsi_insn/1 [length = 2]
pop {r4, r5} @ @ 165 *load_multiple_with_writeback [length = 4]
bx lr @ @ 166 *thumb2_return [length = 4]
.L12:
mov r0, r3 @ D.4169, maxloops @ 8 *thumb2_movsi_insn/1 [length = 2]
pop {r4, r5} @ @ 137 *load_multiple_with_writeback [length = 4]
bx lr @ @ 138 *thumb2_return [length = 4]
.L22:
movs r0, #0 @ D.4169, @ 11 *thumb2_movsi_shortim [length = 2]
pop {r4, r5} @ @ 173 *load_multiple_with_writeback [length = 4]
bx lr @ @ 174 *thumb2_return [length = 4]
.size countPulseASM, .-countPulseASM
.ident "GCC: (GNU Tools for ARM Embedded Processors) 4.9.3 20150303 (release) [ARM/embedded-4_9-branch revision 221220]"

7
hardware/arduino/sam/platform.txt
View File

@ -22,7 +22,8 @@ compiler.c.cmd=arm-none-eabi-gcc
compiler.c.flags=-c -g -Os {compiler.warning_flags} -ffunction-sections -fdata-sections -nostdlib --param max-inline-insns-single=500 -Dprintf=iprintf -MMD compiler.c.flags=-c -g -Os {compiler.warning_flags} -ffunction-sections -fdata-sections -nostdlib --param max-inline-insns-single=500 -Dprintf=iprintf -MMD
compiler.c.elf.cmd=arm-none-eabi-gcc compiler.c.elf.cmd=arm-none-eabi-gcc
compiler.c.elf.flags=-Os -Wl,--gc-sections compiler.c.elf.flags=-Os -Wl,--gc-sections
compiler.S.flags=-c -g -x assembler-with-cpp compiler.S.cmd=arm-none-eabi-gcc
compiler.S.flags=-c -g -x assembler-with-cpp -mthumb
compiler.cpp.cmd=arm-none-eabi-g++ compiler.cpp.cmd=arm-none-eabi-g++
compiler.cpp.flags=-c -g -Os {compiler.warning_flags} -ffunction-sections -fdata-sections -nostdlib -fno-threadsafe-statics --param max-inline-insns-single=500 -fno-rtti -fno-exceptions -Dprintf=iprintf -MMD compiler.cpp.flags=-c -g -Os {compiler.warning_flags} -ffunction-sections -fdata-sections -nostdlib -fno-threadsafe-statics --param max-inline-insns-single=500 -fno-rtti -fno-exceptions -Dprintf=iprintf -MMD
compiler.ar.cmd=arm-none-eabi-ar compiler.ar.cmd=arm-none-eabi-ar
@ -42,6 +43,7 @@ build.extra_flags=
compiler.c.extra_flags= compiler.c.extra_flags=
compiler.c.elf.extra_flags= compiler.c.elf.extra_flags=
compiler.cpp.extra_flags= compiler.cpp.extra_flags=
compiler.S.extra_flags=
compiler.ar.extra_flags= compiler.ar.extra_flags=
compiler.elf2hex.extra_flags= compiler.elf2hex.extra_flags=
@ -66,6 +68,9 @@ recipe.c.o.pattern="{compiler.path}{compiler.c.cmd}" {compiler.c.flags} -mcpu={b
## Compile c++ files ## Compile c++ files
recipe.cpp.o.pattern="{compiler.path}{compiler.cpp.cmd}" {compiler.cpp.flags} -mcpu={build.mcu} -DF_CPU={build.f_cpu} -DARDUINO={runtime.ide.version} -DARDUINO_{build.board} -DARDUINO_ARCH_{build.arch} {compiler.cpp.extra_flags} {build.extra_flags} {compiler.libsam.c.flags} {includes} "{source_file}" -o "{object_file}" recipe.cpp.o.pattern="{compiler.path}{compiler.cpp.cmd}" {compiler.cpp.flags} -mcpu={build.mcu} -DF_CPU={build.f_cpu} -DARDUINO={runtime.ide.version} -DARDUINO_{build.board} -DARDUINO_ARCH_{build.arch} {compiler.cpp.extra_flags} {build.extra_flags} {compiler.libsam.c.flags} {includes} "{source_file}" -o "{object_file}"
## Compile S files
recipe.S.o.pattern="{compiler.path}{compiler.S.cmd}" {compiler.S.flags} -mcpu={build.mcu} -DF_CPU={build.f_cpu} -DARDUINO={runtime.ide.version} -DARDUINO_{build.board} -DARDUINO_ARCH_{build.arch} {compiler.S.extra_flags} {build.extra_flags} {compiler.libsam.c.flags} {includes} "{source_file}" -o "{object_file}"
## Create archives ## Create archives
recipe.ar.pattern="{compiler.path}{compiler.ar.cmd}" {compiler.ar.flags} {compiler.ar.extra_flags} "{build.path}/{archive_file}" "{object_file}" recipe.ar.pattern="{compiler.path}{compiler.ar.cmd}" {compiler.ar.flags} {compiler.ar.extra_flags} "{build.path}/{archive_file}" "{object_file}"