View source for Memory Map

This is an old revision of this page, as edited by RemmyLee at 02:22, 23 October 2026. Publishing it replaces the current version.
← Memory Map
You do not have permission to edit this page. Log in to edit.
---
title: Memory Map
type: component
summary: Logical and physical address spaces of the PlayStation CPU.
category: Hardware
---

## Overview

The space a program handles is the logical space. A logical address is 32 bits.[^hw24]

Logical space maps onto physical space several times over. A physical address is an address in the installed memory device.[^hw24]

Access to a logical address with no physical memory behind it raises a Bus Error exception.[^hw24]

The R3000 TLB is not present, so the mapping is fixed.[^hw23]

## Physical Memory

Physical memory has a 64MB system area. Main memory ends at 0x1FFFFF on the PlayStation and at 0x7FFFFF on the developer system.[^hw23]

## Segments

Logical space is divided into the following segments:

Table: Memory maps

| Logic Space | Segment title | Cache |
| --- | --- | --- |
| 0x00000000 to physical space MAX | A | Effective |
| 0x1F800000 to 0x1F8003FF | S | Not effective |
| 0x1F801000 to 0x1FBFFFFF | X | Not effective |
| 0x1FC00000 to 0x1FC7FFFF | P | Effective |
| 0x80000000 to 0x80000000 + physical space MAX | B | Effective |
| 0x9FC00000 to 0x9FC7FFFF | Q | Effective |
| 0xA0000000 to 0xA0000000 + physical space MAX | C | Not effective |
| 0xBFC00000 to 0xBFC7FFFF | R | Not effective |

The Cache column refers to the I-cache. A segment is a block of the R3000 memory space and differs from a segment of the 8086 series.[^hw24]

## Devices

The segments map onto the following devices:

Table: Segments and devices

| Logic Space | Corresponding Logic Memory Segment | Device |
| --- | --- | --- |
| 0x00000000 to MAX | A+B+C | Main Memory (RAM) |
| 0x1F800000 to 0x1F8003FF | S | Scratchpad (D-cache) |
| 0x1F801000 to 0x1FBFFFFF | X | Hardware Register |
| 0x1FC00000 to 0x1FC7FFFF | P+Q+R | Boot ROM |

Sony does not disclose the addresses inside the OS ROM. Access to the ROM is prohibited.[^hw23]

The [CPU](/hardware/cpu/) page describes the caches and the scratchpad.

## References

[^hw23]: Sony Computer Entertainment Inc. PlayStation Hardware. August 1998. Page 2-3, Figure 2-1.
[^hw24]: Sony Computer Entertainment Inc. PlayStation Hardware. August 1998. Page 2-4, Figure 2-2, Table 2-2.