FENIX_kernel/arch/i386/gdt.c

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2020-12-02 02:59:57 +00:00
void encode_gdt_entry(unsigned short int * target, struct GDT source) {
if((source.limit > 65536) && ((source.limit & 0xFFF) != 0xFFF)) {
/* This needs to error out. */
return;
}
if(source.limit > 65536) {
/* Granularity adjustments */
source.limit = source.limit >> 12;
target[6] = 0xC0;
}
else {
target[6] = 0x40;
}
/* Encode limit */
target[0] = source.limit & 0xFF;
target[1] = (source.limit >> 8) & 0xFF;
target[6] |= (source.limit >> 16) & 0xF;
/* Encode base */
target[2] = source.base & 0xFF;
target[3] = (source.base >> 8) & 0xFF;
target[4] = (source.base >> 16) & 0xFF;
target[7] = (source.base >> 24) & 0xFF;
/* Encode type */
target[5] = source.type;
}