esp-idf/components/esp32/test/test_fp.c

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2021-06-03 07:40:09 -04:00
/*
* SPDX-FileCopyrightText: 2021 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <math.h>
#include <stdio.h>
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#include "soc/cpu.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/semphr.h"
#include "unity.h"
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#include "test_utils.h"
/* Note: these functions are included here for unit test purposes. They are not needed for writing
* normal code. If writing standard C floating point code, libgcc should correctly include implementations
* that use the floating point registers correctly. */
static float addsf(float a, float b)
{
float result;
asm volatile (
"wfr f0, %1\n"
"wfr f1, %2\n"
"add.s f2, f0, f1\n"
"rfr %0, f2\n"
:"=r"(result):"r"(a), "r"(b)
);
return result;
}
static float mulsf(float a, float b)
{
float result;
asm volatile (
"wfr f0, %1\n"
"wfr f1, %2\n"
"mul.s f2, f0, f1\n"
"rfr %0, f2\n"
:"=r"(result):"r"(a), "r"(b)
);
return result;
}
static float divsf(float a, float b)
{
float result;
asm volatile (
"wfr f0, %1\n"
"wfr f1, %2\n"
"div0.s f3, f1 \n"
"nexp01.s f4, f1 \n"
"const.s f5, 1 \n"
"maddn.s f5, f4, f3 \n"
"mov.s f6, f3 \n"
"mov.s f7, f1 \n"
"nexp01.s f8, f0 \n"
"maddn.s f6, f5, f3 \n"
"const.s f5, 1 \n"
"const.s f2, 0 \n"
"neg.s f9, f8 \n"
"maddn.s f5,f4,f6 \n"
"maddn.s f2, f9, f3 \n"
"mkdadj.s f7, f0 \n"
"maddn.s f6,f5,f6 \n"
"maddn.s f9,f4,f2 \n"
"const.s f5, 1 \n"
"maddn.s f5,f4,f6 \n"
"maddn.s f2,f9,f6 \n"
"neg.s f9, f8 \n"
"maddn.s f6,f5,f6 \n"
"maddn.s f9,f4,f2 \n"
"addexpm.s f2, f7 \n"
"addexp.s f6, f7 \n"
"divn.s f2,f9,f6\n"
"rfr %0, f2\n"
:"=r"(result):"r"(a), "r"(b)
);
return result;
}
static float sqrtsf(float a)
{
float result;
asm volatile (
"wfr f0, %1\n"
"sqrt0.s f2, f0\n"
"const.s f5, 0\n"
"maddn.s f5, f2, f2\n"
"nexp01.s f3, f0\n"
"const.s f4, 3\n"
"addexp.s f3, f4\n"
"maddn.s f4, f5, f3\n"
"nexp01.s f5, f0\n"
"neg.s f6, f5\n"
"maddn.s f2, f4, f2\n"
"const.s f1, 0\n"
"const.s f4, 0\n"
"const.s f7, 0\n"
"maddn.s f1, f6, f2\n"
"maddn.s f4, f2, f3\n"
"const.s f6, 3\n"
"maddn.s f7, f6, f2\n"
"maddn.s f5, f1, f1\n"
"maddn.s f6, f4, f2\n"
"neg.s f3, f7\n"
"maddn.s f1, f5, f3\n"
"maddn.s f7, f6, f7\n"
"mksadj.s f2, f0\n"
"nexp01.s f5, f0\n"
"maddn.s f5, f1, f1\n"
"neg.s f3, f7\n"
"addexpm.s f1, f2\n"
"addexp.s f3, f2\n"
"divn.s f1, f5, f3\n"
"rfr %0, f1\n"
:"=r"(result):"r"(a)
);
return result;
}
TEST_CASE("test FP add", "[fp]")
{
float a = 100.0f;
float b = 0.5f;
float c = addsf(a, b);
float eps = c - 100.5f;
printf("a=%g b=%g c=%g eps=%g\r\n", a, b, c, eps);
TEST_ASSERT_TRUE(fabs(eps) < 0.000001);
}
TEST_CASE("test FP mul", "[fp]")
{
float a = 100.0f;
float b = 0.05f;
float c = mulsf(a, b);
float eps = c - 5.0f;
printf("a=%g b=%g c=%g eps=%g\r\n", a, b, c, eps);
TEST_ASSERT_TRUE(fabs(eps) < 0.000001);
}
TEST_CASE("test FP div", "[fp]")
{
float a = 100.0f;
float b = 5.0f;
float c = divsf(a, b);
float eps = c - 20.0f;
printf("a=%g b=%g c=%g eps=%g\r\n", a, b, c, eps);
TEST_ASSERT_TRUE(fabs(eps) < 0.000001);
}
TEST_CASE("test FP sqrt", "[fp]")
{
float a = 100.0f;
float c = sqrtsf(a);
float eps = c - 10.0f;
printf("a=%g c=%g eps=%g\r\n", a, c, eps);
TEST_ASSERT_TRUE(fabs(eps) < 0.000001);
}
struct TestFPState {
int fail;
SemaphoreHandle_t done;
};
static const int testFpIter = 100000;
static void tskTestFP(void *pvParameters)
{
struct TestFPState *state = (struct TestFPState *) pvParameters;
for (int i = 0; i < testFpIter; ++i) {
// calculate zero in a slightly obscure way
float y = sqrtsf(addsf(1.0f, divsf(mulsf(sqrtsf(2), sqrtsf(2)), 2.0f)));
y = mulsf(y, y);
y = addsf(y, -2.0f);
// check that result is not far from zero
float eps = fabs(y);
if (eps > 1e-6f) {
state->fail++;
printf("%s: i=%d y=%f eps=%f\r\n", __func__, i, y, eps);
}
}
TEST_ASSERT(xSemaphoreGive(state->done));
vTaskDelete(NULL);
}
TEST_CASE("context switch saves FP registers", "[fp]")
{
struct TestFPState state = {
.done = xSemaphoreCreateCounting(4, 0)
};
TEST_ASSERT_NOT_NULL(state.done);
const int prio = UNITY_FREERTOS_PRIORITY + 1;
TEST_ASSERT(xTaskCreatePinnedToCore(tskTestFP, "tsk1", 2048, &state, prio, NULL, 0));
TEST_ASSERT(xTaskCreatePinnedToCore(tskTestFP, "tsk2", 2048, &state, prio, NULL, 0));
TEST_ASSERT(xTaskCreatePinnedToCore(tskTestFP, "tsk3", 2048, &state, prio, NULL, portNUM_PROCESSORS - 1));
TEST_ASSERT(xTaskCreatePinnedToCore(tskTestFP, "tsk4", 2048, &state, prio, NULL, 0));
for (int i = 0; i < 4; ++i) {
TEST_ASSERT(xSemaphoreTake(state.done, pdMS_TO_TICKS(5000)));
}
vSemaphoreDelete(state.done);
if (state.fail) {
const int total = testFpIter * 4;
printf("Failed: %d, total: %d\r\n", state.fail, total);
}
TEST_ASSERT(state.fail == 0);
}
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/* Note: not static, to avoid optimisation of const result */
float IRAM_ATTR test_fp_benchmark_fp_divide(int counts, unsigned *cycles)
{
float f = MAXFLOAT;
uint32_t before, after;
RSR(CCOUNT, before);
for (int i = 0; i < counts; i++) {
f /= 1.000432f;
}
RSR(CCOUNT, after);
*cycles = (after - before) / counts;
return f;
}
TEST_CASE("floating point division performance", "[fp]")
{
const unsigned COUNTS = 1000;
unsigned cycles = 0;
// initialize fpu
volatile __attribute__((unused)) float dummy = sqrtf(rand());
float f = test_fp_benchmark_fp_divide(COUNTS, &cycles);
printf("%d divisions from %f = %f\n", COUNTS, MAXFLOAT, f);
printf("Per division = %d cycles\n", cycles);
TEST_PERFORMANCE_LESS_THAN(CYCLES_PER_DIV, "%d cycles", cycles);
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}
/* Note: not static, to avoid optimisation of const result */
float IRAM_ATTR test_fp_benchmark_fp_sqrt(int counts, unsigned *cycles)
{
float f = MAXFLOAT;
uint32_t before, after;
RSR(CCOUNT, before);
for (int i = 0; i < counts; i++) {
f = sqrtf(f);
}
RSR(CCOUNT, after);
*cycles = (after - before) / counts;
return f;
}
TEST_CASE("floating point square root performance", "[fp]")
{
const unsigned COUNTS = 200;
unsigned cycles = 0;
// initialize fpu
volatile float __attribute__((unused)) dummy = sqrtf(rand());
float f = test_fp_benchmark_fp_sqrt(COUNTS, &cycles);
printf("%d square roots from %f = %f\n", COUNTS, MAXFLOAT, f);
printf("Per sqrt = %d cycles\n", cycles);
TEST_PERFORMANCE_LESS_THAN(CYCLES_PER_SQRT, "%d cycles", cycles);
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}