Intel® Core™ Ultra Processors for H-series and U-series Platforms CFG and MEM Registers
| ID | Date | Version | Classification |
|---|---|---|---|
| 795258 | 12/14/2023 | Public |
A newer version of this document is available. Customers should click here to go to the newest version.
Top of Memory (TOM_0_0_0_PCI) – Offset a0
This Register contains the size of physical memory.
BIOS determines the memory size reported to the OS using this Register.
| Bit Range | Default | Access | Field Name and Description |
|---|---|---|---|
| 63:42 | 0h | RO | Reserved |
| 41:20 | 7ffffh | RW/L | (TOM) This register reflects the total amount of populated physical memory. This is NOT necessarily the highest main memory address (holes may exist in main memory address map due to addresses allocated for memory mapped IO). These bits correspond to address bits 41:20 (1MB granularity). Bits 19:0 are assumed to be 0. All the bits in this register are locked in Intel TXT mode. |
| 19:1 | 0h | RO | Reserved |
| 0 | 0h | RW/L | (LOCK) This bit will lock all writable settings in this register, including itself. |