/*
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-m0plus -mthumb -c -Os -W -ffunction-sections -fdata-sections \
-nostdlib --param max-inline-insns-single=500 -fno-exceptions -MMD \
-DF_CPU=48000000L -DARDUINO=10602 -DARDUINO_SAMD_ZERO -DARDUINO_ARCH_SAMD \
-D__SAMD21G18A__ -DUSB_VID=0x2341 -DUSB_PID=0x004d -DUSBCON \
-DUSB_MANUFACTURER="Arduino LLC" -DUSB_PRODUCT="Arduino Zero" \
-I/Code/arduino/build/linux/work/hardware/tools/CMSIS/CMSIS/Include/ \
-I/Code/arduino/build/linux/work/hardware/tools/CMSIS/Device/ATMEL/ \
-I/Code/arduino/build/linux/work/hardware/arduino/samd/cores/arduino \
-I/Code/arduino/build/linux/work/hardware/arduino/samd/variants/arduino_zero \
count.c -Wa,-ahlmsd=output.lst -dp -fverbose-asm -S
The result has been slightly edited to increase readability.
*/
.cpu cortex-m0plus
.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, 4 @ Tag_ABI_optimization_goals
.eabi_attribute 34, 0 @ Tag_CPU_unaligned_access
.eabi_attribute 18, 4 @ Tag_ABI_PCS_wchar_t
.file "count.c"
@ GNU C (GNU Tools for ARM Embedded Processors (Arduino build)) version 4.8.3 20140228 (release) [ARM/embedded-4_8-branch revision 208322] (arm-none-eabi)
@ compiled by GNU C version 4.3.2, 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 /Code/arduino/build/linux/work/hardware/tools/CMSIS/CMSIS/Include/
@ -I /Code/arduino/build/linux/work/hardware/tools/CMSIS/Device/ATMEL/
@ -I /Code/arduino/build/linux/work/hardware/arduino/samd/cores/arduino
@ -I /Code/arduino/build/linux/work/hardware/arduino/samd/variants/arduino_zero
@ -imultilib armv6-m
@ -iprefix /Code/arduino/build/linux/work/hardware/tools/gcc-arm-none-eabi-4.8.3-2014q1/bin/../lib/gcc/arm-none-eabi/4.8.3/
@ -isysroot /Code/arduino/build/linux/work/hardware/tools/gcc-arm-none-eabi-4.8.3-2014q1/bin/../arm-none-eabi
@ -MMD count.d -D__USES_INITFINI__ -D F_CPU=48000000L -D ARDUINO=10602
@ -D ARDUINO_SAMD_ZERO -D ARDUINO_ARCH_SAMD -D __SAMD21G18A__
@ -D USB_VID=0x2341 -D USB_PID=0x004d -D USBCON
@ -D USB_MANUFACTURER=Arduino LLC -D USB_PRODUCT=Arduino Zero count.c
@ -mcpu=cortex-m0plus -mthumb -Os -Wextra -ffunction-sections
@ -fdata-sections -fno-exceptions -fverbose-asm
@ --param max-inline-insns-single=500
@ 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
@ -fdwarf2-cfi-asm -fearly-inlining -feliminate-unused-debug-types
@ -fexpensive-optimizations -fforward-propagate -ffunction-cse
@ -ffunction-sections -fgcse -fgcse-lm -fgnu-runtime
@ -fguess-branch-probability -fhoist-adjacent-loads -fident -fif-conversion
@ -fif-conversion2 -findirect-inlining -finline -finline-atomics
@ -finline-functions -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 -fivopts -fkeep-static-consts
@ -fleading-underscore -fmath-errno -fmerge-constants -fmerge-debug-strings
@ -fomit-frame-pointer -foptimize-register-move -foptimize-sibling-calls
@ -fpartial-inlining -fpeephole -fpeephole2 -fprefetch-loop-arrays
@ -freg-struct-return -fregmove -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-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-slp-vectorize -ftree-slsr -ftree-sra -ftree-switch-conversion
@ -ftree-tail-merge -ftree-ter -ftree-vect-loop-version -ftree-vrp
@ -funit-at-a-time -fverbose-asm -fzero-initialized-in-bss -mlittle-endian
@ -mpic-data-is-text-relative -msched-prolog -mthumb
@ -mvectorize-with-neon-quad
.section .text.countPulseASM,"ax",%progbits
.align 1
.global countPulseASM
.code 16
.thumb_func
.type countPulseASM, %function
countPulseASM:
push {r4, r5, lr} @ @ 112 *push_multi [length = 2]
.L2:
ldr r4, [r0] @ D.11539, *port_7(D) @ 22 *thumb1_movsi_insn/7 [length = 2]
and r4, r1 @ D.11539, bit @ 24 *thumb1_andsi3_insn [length = 2]
cmp r4, r2 @ D.11539, stateMask @ 25 cbranchsi4_insn/1 [length = 4]
bne .L5 @,
sub r3, r3, #1 @ maxloops, @ 17 *thumb1_addsi3/2 [length = 2]
cmp r3, #0 @ maxloops, @ 18 cbranchsi4_insn/1 [length = 4]
bne .L2 @,
b .L10 @ @ 127 *thumb_jump [length = 2]
.L6:
sub r3, r3, #1 @ maxloops, @ 30 *thumb1_addsi3/2 [length = 2]
cmp r3, #0 @ maxloops, @ 31 cbranchsi4_insn/1 [length = 4]
beq .L10 @,
.L5:
ldr r4, [r0] @ D.11539, *port_7(D) @ 35 *thumb1_movsi_insn/7 [length = 2]
and r4, r1 @ D.11539, bit @ 37 *thumb1_andsi3_insn [length = 2]
cmp r4, r2 @ D.11539, stateMask @ 38 cbranchsi4_insn/1 [length = 4]
bne .L6 @,
mov r4, #0 @ width, @ 7 *thumb1_movsi_insn/2 [length = 2]
.L7:
ldr r5, [r0] @ D.11539, *port_7(D) @ 48 *thumb1_movsi_insn/7 [length = 2]
and r5, r1 @ D.11539, bit @ 50 *thumb1_andsi3_insn [length = 2]
cmp r5, r2 @ D.11539, stateMask @ 51 cbranchsi4_insn/1 [length = 4]
bne .L13 @,
add r4, r4, #1 @ width, @ 43 *thumb1_addsi3/1 [length = 2]
cmp r4, r3 @ width, maxloops @ 44 cbranchsi4_insn/1 [length = 4]
bne .L7 @,
mov r0, #0 @ D.11539, @ 11 *thumb1_movsi_insn/2 [length = 2]
b .L3 @ @ 130 *thumb_jump [length = 2]
.L13:
mov r0, r4 @ D.11539, width @ 9 *thumb1_movsi_insn/1 [length = 2]
b .L3 @ @ 132 *thumb_jump [length = 2]
.L10:
mov r0, r3 @ D.11539, maxloops @ 8 *thumb1_movsi_insn/1 [length = 2]
.L3:
@ sp needed @ @ 115 force_register_use [length = 0]
pop {r4, r5, pc}
.size countPulseASM, .-countPulseASM
.ident "GCC: (GNU Tools for ARM Embedded Processors (Arduino build)) 4.8.3 20140228 (release) [ARM/embedded-4_8-branch revision 208322]"