esp-open-rtos/examples/experiments/unaligned_load/unaligned_load.c

/* Very basic example that just demonstrates we can run at all!
 */
#include "esp/rom.h"
#include "esp/timer.h"
#include "espressif/esp_common.h"
#include "esp/uart.h"
#include "FreeRTOS.h"
#include "task.h"
#include "queue.h"

#include "string.h"
#include "strings.h"

#define TESTSTRING "O hai there! %d %d %d"

const char *dramtest = TESTSTRING;
const __attribute__((section(".iram1.notrodata"))) char iramtest[] = TESTSTRING;
const __attribute__((section(".text.notrodata"))) char iromtest[] = TESTSTRING;

static inline uint32_t get_ccount (void)
{
    uint32_t ccount;
    asm volatile ("rsr.ccount %0" : "=a" (ccount));
    return ccount;
}

typedef void (* test_with_fn_t)(const char *string);

char buf[64];

void test_memcpy_aligned(const char *string)
{
    memcpy(buf, string, 16);
}

void test_memcpy_unaligned(const char *string)
{
    memcpy(buf, string, 15);
}

void test_memcpy_unaligned2(const char *string)
{
    memcpy(buf, string+1, 15);
}

void test_strcpy(const char *string)
{
    strcpy(buf, string);
}

void test_sprintf(const char *string)
{
    sprintf(buf, string, 1, 2, 3);
}

void test_sprintf_arg(const char *string)
{
    sprintf(buf, "%s", string);
}

void test_naive_strcpy(const char *string)
{
    char *to = buf;
    while((*to++ = *string++))
        ;
}

void test_naive_strcpy_a0(const char *string)
{
    asm volatile (
"            mov          a8, %0    \n"
"            mov          a9, %1    \n"
"tns_loop%=: l8ui         a0, a9, 0 \n"
"            addi.n       a9, a9, 1 \n"
"            s8i          a0, a8, 0 \n"
"            addi.n       a8, a8, 1 \n"
"            bnez         a0, tns_loop%=\n"
        : : "r" (buf), "r" (string) : "a0", "a8", "a9");
}

void test_naive_strcpy_a2(const char *string)
{
    asm volatile (
"            mov          a8, %0    \n"
"            mov          a9, %1    \n"
"tns_loop%=: l8ui         a2, a9, 0 \n"
"            addi.n       a9, a9, 1 \n"
"            s8i          a2, a8, 0 \n"
"            addi.n       a8, a8, 1 \n"
"            bnez         a2, tns_loop%=\n"
        : : "r" (buf), "r" (string) : "a2", "a8", "a9");
}

void test_naive_strcpy_a3(const char *string)
{
    asm volatile (
"            mov          a8, %0    \n"
"            mov          a9, %1    \n"
"tns_loop%=: l8ui         a3, a9, 0 \n"
"            addi.n       a9, a9, 1 \n"
"            s8i          a3, a8, 0 \n"
"            addi.n       a8, a8, 1 \n"
"            bnez         a3, tns_loop%=\n"
        : : "r" (buf), "r" (string) : "a3", "a8", "a9");
}

void test_naive_strcpy_a4(const char *string)
{
    asm volatile (
"            mov          a8, %0    \n"
"            mov          a9, %1    \n"
"tns_loop%=: l8ui         a4, a9, 0 \n"
"            addi.n       a9, a9, 1 \n"
"            s8i          a4, a8, 0 \n"
"            addi.n       a8, a8, 1 \n"
"            bnez         a4, tns_loop%=\n"
        : : "r" (buf), "r" (string) : "a4", "a8", "a9");
}

void test_naive_strcpy_a5(const char *string)
{
    asm volatile (
"            mov          a8, %0    \n"
"            mov          a9, %1    \n"
"tns_loop%=: l8ui         a5, a9, 0 \n"
"            addi.n       a9, a9, 1 \n"
"            s8i          a5, a8, 0 \n"
"            addi.n       a8, a8, 1 \n"
"            bnez         a5, tns_loop%=\n"
        : : "r" (buf), "r" (string) : "a5", "a8", "a9");
}

void test_naive_strcpy_a6(const char *string)
{
    asm volatile (
"            mov          a8, %0    \n"
"            mov          a9, %1    \n"
"tns_loop%=: l8ui         a6, a9, 0 \n"
"            addi.n       a9, a9, 1 \n"
"            s8i          a6, a8, 0 \n"
"            addi.n       a8, a8, 1 \n"
"            bnez         a6, tns_loop%=\n"
        : : "r" (buf), "r" (string) : "a6", "a8", "a9");
}

void test_l16si(const char *string)
{
    /* This follows most of the l16si path, but as the
     values in the string are all 7 bit none of them get sign extended.

    See separate test_sign_extension function which validates
    sign extension works as expected.
    */
    int16_t *src_int16 = (int16_t *)string;
    int32_t *dst_int32 = (int32_t *)buf;
    dst_int32[0] = src_int16[0];
    dst_int32[1] = src_int16[1];
    dst_int32[2] = src_int16[2];
}

#define TEST_REPEATS 1000

void test_noop(const char *string)
{

}

uint32_t IRAM run_test(const char *string, test_with_fn_t testfn, const char *testfn_label, uint32_t nullvalue, bool evict_cache)
{
    printf(" .. against %30s: ", testfn_label);
    vPortEnterCritical();
    uint32_t before = get_ccount();
    for(int i = 0; i < TEST_REPEATS; i++) {
        testfn(string);
        if(evict_cache) {
            Cache_Read_Disable();
            Cache_Read_Enable(0,0,1);
        }
    }
    uint32_t after = get_ccount();
    vPortExitCritical();
    uint32_t instructions = (after-before)/TEST_REPEATS - nullvalue;
    printf("%5d instructions\r\n", instructions);
    return instructions;
}

void test_string(const char *string, char *label, bool evict_cache)
{
    printf("Testing %s (%p) '%s'\r\n", label, string, string);
    printf("Formats as: '");
    printf(string, 1, 2, 3);
    printf("'\r\n");
    uint32_t nullvalue = run_test(string, test_noop, "null op", 0, evict_cache);
    run_test(string, test_memcpy_aligned, "memcpy - aligned len", nullvalue, evict_cache);
    run_test(string, test_memcpy_unaligned, "memcpy - unaligned len", nullvalue, evict_cache);
    run_test(string, test_memcpy_unaligned2, "memcpy - unaligned start&len", nullvalue, evict_cache);
    run_test(string, test_strcpy, "strcpy", nullvalue, evict_cache);
    run_test(string, test_naive_strcpy, "naive strcpy", nullvalue, evict_cache);
    run_test(string, test_naive_strcpy_a0, "naive strcpy (a0)", nullvalue, evict_cache);
    run_test(string, test_naive_strcpy_a2, "naive strcpy (a2)", nullvalue, evict_cache);
    run_test(string, test_naive_strcpy_a3, "naive strcpy (a3)", nullvalue, evict_cache);
    run_test(string, test_naive_strcpy_a4, "naive strcpy (a4)", nullvalue, evict_cache);
    run_test(string, test_naive_strcpy_a5, "naive strcpy (a5)", nullvalue, evict_cache);
    run_test(string, test_naive_strcpy_a6, "naive strcpy (a6)", nullvalue, evict_cache);
    run_test(string, test_sprintf, "sprintf", nullvalue, evict_cache);
    run_test(string, test_sprintf_arg, "sprintf format arg", nullvalue, evict_cache);
    run_test(string, test_l16si, "load as l16si", nullvalue, evict_cache);
}

static void test_isr();
static void test_sign_extension();
static void test_system_interaction();
void sanity_tests(void);

void user_init(void)
{
    uart_set_baud(0, 115200);

    gpio_enable(2, GPIO_OUTPUT); /* used for LED debug */
    gpio_write(2, 1); /* active low */

    printf("\r\n\r\nSDK version:%s\r\n", sdk_system_get_sdk_version());
    sanity_tests();
    test_string(dramtest, "DRAM", 0);
    test_string(iramtest, "IRAM", 0);
    test_string(iromtest, "Cached flash", 0);
    test_string(iromtest, "'Uncached' flash", 1);

    test_isr();
    test_sign_extension();

    xTaskHandle taskHandle;
    xTaskCreate(test_system_interaction, (signed char *)"interactionTask", 256, &taskHandle, 2, NULL);
}

static volatile bool frc1_ran;
static volatile bool frc1_finished;
static volatile char frc1_buf[80];

static void frc1_interrupt_handler(void)
{
    frc1_ran = true;
    timer_set_run(FRC1, false);
    strcpy((char *)frc1_buf, iramtest);
    frc1_finished = true;
}

static void test_isr()
{
    printf("Testing behaviour inside ISRs...\r\n");
    timer_set_interrupts(FRC1, false);
    timer_set_run(FRC1, false);
    _xt_isr_attach(INUM_TIMER_FRC1, frc1_interrupt_handler);
    timer_set_frequency(FRC1, 1000);
    timer_set_interrupts(FRC1, true);
    timer_set_run(FRC1, true);
    sdk_os_delay_us(2000);

    if(!frc1_ran)
        printf("ERROR: FRC1 timer exception never fired.\r\n");
    else if(!frc1_finished)
        printf("ERROR: FRC1 timer exception never finished.\r\n");
    else if(strcmp((char *)frc1_buf, iramtest))
        printf("ERROR: FRC1 strcpy from IRAM failed.\r\n");
    else
        printf("PASSED\r\n");
}

const volatile __attribute__((section(".iram1.notliterals"))) int16_t unsigned_shorts[] = { -3, -4, -5, -32767, 44 };

static void test_sign_extension()
{
    /* this step seems to be necessary so the compiler will actually generate l16si */
    int16_t *shorts_p = (int16_t *)unsigned_shorts;
    if(shorts_p[0] == -3 && shorts_p[1] == -4 && shorts_p[2] == -5 && shorts_p[3] == -32767 && shorts_p[4] == 44)
    {
        printf("l16si sign extension PASSED.\r\n");
    } else {
        printf("ERROR: l16si sign extension failed. Got values %d %d %d %d %d\r\n", shorts_p[0], shorts_p[1], shorts_p[2], shorts_p[3], shorts_p[4]);
    }
}


/* test that running unaligned loads in a running FreeRTOS system doesn't break things

   The following tests run inside a FreeRTOS task, after everything else.
*/
static void test_system_interaction()
{
    uint32_t start = xTaskGetTickCount();
    printf("Starting system/timer interaction test (takes approx 30 seconds)...\n");
    for(int i = 0; i < 200*1000; i++) {
        test_naive_strcpy_a0(iromtest);
        test_naive_strcpy_a2(iromtest);
        test_naive_strcpy_a3(iromtest);
        test_naive_strcpy_a4(iromtest);
        test_naive_strcpy_a5(iromtest);
        test_naive_strcpy_a6(iromtest);
        /*
        const volatile char *string = iromtest;
        volatile char *to = dest;
        while((*to++ = *string++))
            ;
        */
    }
    uint32_t ticks = xTaskGetTickCount() - start;
    printf("Timer interaction test PASSED after %dms.\n", ticks*portTICK_RATE_MS);
    while(1) {}
}

/* The following "sanity tests" are designed to try to execute every code path
 * of the LoadStoreError handler, with a variety of offsets and data values
 * designed to catch any mask/shift errors, sign-extension bugs, etc */

/* (Contrary to expectations, 'mov a15, a15' in Xtensa is not technically a
 * no-op, but is officially "undefined and reserved for future use", so we need
 * a special case in the case where reg == "a15" so we don't end up generating
 * those opcodes.  GCC is smart enough to optimize away the whole conditional
 * and just insert the correct asm block, since `reg` is a static argument.) */
#define LOAD_VIA_REG(op, reg, addr, var) \
    if (strcmp(reg, "a15")) { \
        asm volatile ( \
        "mov a15, " reg "\n\t" \
        op " " reg ", %1, 0\n\t" \
        "mov %0, " reg "\n\t" \
        "mov " reg ", a15\n\t" \
        : "=r" (var) : "r" (addr) : "a15" ); \
    } else { \
        asm volatile ( \
        op " " reg ", %1, 0\n\t" \
        "mov %0, " reg "\n\t" \
        : "=r" (var) : "r" (addr) : "a15" ); \
    }

#define TEST_LOAD(op, reg, addr, value) \
    { \
        int32_t result; \
        LOAD_VIA_REG(op, reg, addr, result); \
        if (result != value) sanity_test_failed(op, reg, addr, value, result); \
    }

void sanity_test_failed(const char *testname, const char *reg, const void *addr, int32_t value, int32_t result) {
    uint32_t actual_data = *(uint32_t *)((uint32_t)addr & 0xfffffffc);

    printf("*** SANITY TEST FAILED: '%s %s' from %p (underlying 32-bit value: 0x%x): Expected 0x%08x (%d), got 0x%08x (%d)\n", testname, reg, addr, actual_data, value, value, result, result);
}

const __attribute__((section(".iram1.notrodata"))) char sanity_test_data[] = {
    0x01, 0x55, 0x7e, 0x2a, 0x81, 0xd5, 0xfe, 0xaa
};

void sanity_test_l8ui(const void *addr, int32_t value) {
    TEST_LOAD("l8ui", "a0", addr, value);
    TEST_LOAD("l8ui", "a1", addr, value);
    TEST_LOAD("l8ui", "a2", addr, value);
    TEST_LOAD("l8ui", "a3", addr, value);
    TEST_LOAD("l8ui", "a4", addr, value);
    TEST_LOAD("l8ui", "a5", addr, value);
    TEST_LOAD("l8ui", "a6", addr, value);
    TEST_LOAD("l8ui", "a7", addr, value);
    TEST_LOAD("l8ui", "a8", addr, value);
    TEST_LOAD("l8ui", "a9", addr, value);
    TEST_LOAD("l8ui", "a10", addr, value);
    TEST_LOAD("l8ui", "a11", addr, value);
    TEST_LOAD("l8ui", "a12", addr, value);
    TEST_LOAD("l8ui", "a13", addr, value);
    TEST_LOAD("l8ui", "a14", addr, value);
    TEST_LOAD("l8ui", "a15", addr, value);
}

void sanity_test_l16ui(const void *addr, int32_t value) {
    TEST_LOAD("l16ui", "a0", addr, value);
    TEST_LOAD("l16ui", "a1", addr, value);
    TEST_LOAD("l16ui", "a2", addr, value);
    TEST_LOAD("l16ui", "a3", addr, value);
    TEST_LOAD("l16ui", "a4", addr, value);
    TEST_LOAD("l16ui", "a5", addr, value);
    TEST_LOAD("l16ui", "a6", addr, value);
    TEST_LOAD("l16ui", "a7", addr, value);
    TEST_LOAD("l16ui", "a8", addr, value);
    TEST_LOAD("l16ui", "a9", addr, value);
    TEST_LOAD("l16ui", "a10", addr, value);
    TEST_LOAD("l16ui", "a11", addr, value);
    TEST_LOAD("l16ui", "a12", addr, value);
    TEST_LOAD("l16ui", "a13", addr, value);
    TEST_LOAD("l16ui", "a14", addr, value);
    TEST_LOAD("l16ui", "a15", addr, value);
}

void sanity_test_l16si(const void *addr, int32_t value) {
    TEST_LOAD("l16si", "a0", addr, value);
    TEST_LOAD("l16si", "a1", addr, value);
    TEST_LOAD("l16si", "a2", addr, value);
    TEST_LOAD("l16si", "a3", addr, value);
    TEST_LOAD("l16si", "a4", addr, value);
    TEST_LOAD("l16si", "a5", addr, value);
    TEST_LOAD("l16si", "a6", addr, value);
    TEST_LOAD("l16si", "a7", addr, value);
    TEST_LOAD("l16si", "a8", addr, value);
    TEST_LOAD("l16si", "a9", addr, value);
    TEST_LOAD("l16si", "a10", addr, value);
    TEST_LOAD("l16si", "a11", addr, value);
    TEST_LOAD("l16si", "a12", addr, value);
    TEST_LOAD("l16si", "a13", addr, value);
    TEST_LOAD("l16si", "a14", addr, value);
    TEST_LOAD("l16si", "a15", addr, value);
}

void sanity_tests(void) {
    printf("== Performing sanity tests (sanity_test_data @ %p)...\n", sanity_test_data);

    sanity_test_l8ui(sanity_test_data + 0, 0x01);
    sanity_test_l8ui(sanity_test_data + 1, 0x55);
    sanity_test_l8ui(sanity_test_data + 2, 0x7e);
    sanity_test_l8ui(sanity_test_data + 3, 0x2a);
    sanity_test_l8ui(sanity_test_data + 4, 0x81);
    sanity_test_l8ui(sanity_test_data + 5, 0xd5);
    sanity_test_l8ui(sanity_test_data + 6, 0xfe);
    sanity_test_l8ui(sanity_test_data + 7, 0xaa);

    sanity_test_l16ui(sanity_test_data + 0, 0x5501);
    sanity_test_l16ui(sanity_test_data + 2, 0x2a7e);
    sanity_test_l16ui(sanity_test_data + 4, 0xd581);
    sanity_test_l16ui(sanity_test_data + 6, 0xaafe);

    sanity_test_l16si(sanity_test_data + 0, 0x5501);
    sanity_test_l16si(sanity_test_data + 2, 0x2a7e);
    sanity_test_l16si(sanity_test_data + 4, -10879);
    sanity_test_l16si(sanity_test_data + 6, -21762);

    printf("== Sanity tests completed.\n");
}