/*
 * p1_emm.c — проверка выделения трёх EMM-страниц и доступа через W3.
 */

#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <sprinter_mem.h>
#include "p1_platform.h"

#define P1_PAGE_SIZE 0x4000u
#define P1_BLOCK     64u

static uint8_t write_buf[P1_BLOCK];
static uint8_t read_buf[P1_BLOCK];

static void make_pattern(uint8_t page_index, uint8_t salt)
{
    uint8_t i;
    for (i = 0; i < P1_BLOCK; i++) {
        write_buf[i] = (uint8_t)(salt ^ (uint8_t)(page_index * 0x41u + i));
        read_buf[i] = 0;
    }
}

static int check_region(uint8_t page, uint8_t page_index,
                        uint16_t offset, uint8_t salt)
{
    make_pattern(page_index, salt);
    bank_write(page, offset, write_buf, P1_BLOCK);
    bank_read(page, offset, read_buf, P1_BLOCK);
    if (memcmp(write_buf, read_buf, P1_BLOCK) != 0) {
        printf("Mismatch: logical=%u phys=%02X offset=%04X\n",
               (unsigned)page_index, (unsigned)page, (unsigned)offset);
        return -1;
    }
    return 0;
}

int p1_test_emm(void)
{
    uint16_t total_before, free_before;
    uint16_t total_after, free_after;
    uint8_t block;
    uint8_t page[3];
    uint8_t i;
    int failed = 0;

    p1_heading("EMM: 3-page allocation and W3 access");
    errno = 0;
    mem_info(&total_before, &free_before);
    printf("Before: total=%u free=%u pages\n",
           (unsigned)total_before, (unsigned)free_before);

    block = mem_alloc_pages(3);
    if (block == 0) {
        printf("mem_alloc_pages(3) failed: errno=%d\n", errno);
        return -1;
    }

    printf("Block id: %u\n", (unsigned)block);
    for (i = 0; i < 3; i++) {
        page[i] = mem_get_page(block, i);
        printf("  logical %u -> physical %02X\n",
               (unsigned)i, (unsigned)page[i]);
        if (page[i] == 0) failed++;
    }

    if (page[0] == page[1] || page[0] == page[2] || page[1] == page[2]) {
        puts("Physical page numbers are not distinct.");
        failed++;
    }

    for (i = 0; i < 3; i++) {
        if (page[i] == 0) continue;
        if (check_region(page[i], i, 0, 0x5A) != 0) failed++;
        if (check_region(page[i], i,
                         (uint16_t)(P1_PAGE_SIZE - P1_BLOCK), 0xA5) != 0) {
            failed++;
        }
    }

    mem_free_block(block);
    mem_info(&total_after, &free_after);
    printf("After : total=%u free=%u pages\n",
           (unsigned)total_after, (unsigned)free_after);

    if (total_before != total_after || free_before != free_after) {
        puts("EMM counters were not restored after free.");
        failed++;
    }

    printf("EMM checks failed: %u\n", (unsigned)failed);
    return failed ? -1 : 0;
}