DOS/ata.c at main · PythonCoders45/DOS · GitHub

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#include"types.h"

#defineATA_PRIMARY_DATA 0x1F0
#defineATA_PRIMARY_ERR 0x1F1
#defineATA_PRIMARY_SECCOUNT 0x1F2
#defineATA_PRIMARY_LBA_LO 0x1F3
#defineATA_PRIMARY_LBA_MID 0x1F4
#defineATA_PRIMARY_LBA_HI 0x1F5
#defineATA_PRIMARY_DRIVE_HEAD 0x1F6
#defineATA_PRIMARY_COMM_REGSTAT 0x1F7

staticinlineuint8_tinb(uint16_tport) {
uint8_tret;
 __asm__ __volatile__ ("inb %1, %0" : "=a"(ret) : "Nd"(port));
returnret;
}

staticinlinevoidoutb(uint16_tport, uint8_tval) {
 __asm__ __volatile__ ("outb %0, %1" : : "a"(val), "Nd"(port));
}

staticinlineuint16_tinw(uint16_tport) {
uint16_tret;
 __asm__ __volatile__ ("inw %1, %0" : "=a"(ret) : "Nd"(port));
returnret;
}

staticinlinevoidoutw(uint16_tport, uint16_tval) {
 __asm__ __volatile__ ("outw %0, %1" : : "a"(val), "Nd"(port));
}

/**
 * @brief Reads a 512-byte sector from disk into memory buffer
 * @param lba Logical Block Address (Sector number on disk)
 * @param buffer Output memory array (at least 512 bytes)
 */
voidata_read_sector(uint32_tlba, uint8_t*buffer) {
outb(ATA_PRIMARY_DRIVE_HEAD, 0xE0 | ((lba >> 24) &0x0F));
outb(ATA_PRIMARY_SECCOUNT, 1);
outb(ATA_PRIMARY_LBA_LO, (uint8_t)lba);
outb(ATA_PRIMARY_LBA_MID, (uint8_t)(lba >> 8));
outb(ATA_PRIMARY_LBA_HI, (uint8_t)(lba >> 16));
outb(ATA_PRIMARY_COMM_REGSTAT, 0x20); // 0x20 = Read Sectors Command

// Wait until disk controller is ready (DRQ bit set, BUSY bit clear)
while ((inb(ATA_PRIMARY_COMM_REGSTAT) &0x88) !=0x08);

// Read 256 16-bit words (512 bytes total)
uint16_t*ptr= (uint16_t*)buffer;
for (inti=0; i<256; i++) {
ptr[i] =inw(ATA_PRIMARY_DATA);
 }
}

/**
 * @brief Writes a 512-byte sector from memory buffer to disk
 */
voidata_write_sector(uint32_tlba, uint8_t*buffer) {
outb(ATA_PRIMARY_DRIVE_HEAD, 0xE0 | ((lba >> 24) &0x0F));
outb(ATA_PRIMARY_SECCOUNT, 1);
outb(ATA_PRIMARY_LBA_LO, (uint8_t)lba);
outb(ATA_PRIMARY_LBA_MID, (uint8_t)(lba >> 8));
outb(ATA_PRIMARY_LBA_HI, (uint8_t)(lba >> 16));
outb(ATA_PRIMARY_COMM_REGSTAT, 0x30); // 0x30 = Write Sectors Command

while ((inb(ATA_PRIMARY_COMM_REGSTAT) &0x88) !=0x08);

uint16_t*ptr= (uint16_t*)buffer;
for (inti=0; i<256; i++) {
outw(ATA_PRIMARY_DATA, ptr[i]);
 }
}