minix/include/arch/i386/memory.h

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/* Physical memory layout on IBM compatible PCs. Only the major, fixed memory
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* areas are detailed here. Known addresses of the BIOS data area are defined
* in <ibm/bios.h>. The map upper memory area (UMA) is only roughly defined
* since the UMA sections may vary in size and locus.
*
* Created: March 2005, Jorrit N. Herder
*/
/* I/O-mapped peripherals. I/O addresses are different from memory addresses
* due to the I/O signal on the ISA bus. Individual I/O ports are defined by
* the drivers that use them or looked up with help of the BIOS.
*/
#define IO_MEMORY_BEGIN 0x0000
#define IO_MEMORY_END 0xFFFF
/* Physical memory layout. Design decisions made for the earliest PCs, caused
* memory to be broken broken into the following four basic pieces:
* - Conventional or base memory: first 640 KB (incl. BIOS data, see below);
* The top of conventional memory is often used by the BIOS to store data.
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* - Upper Memory Area (UMA): upper 384 KB of the first megabyte of memory;
* - High Memory Area (HMA): ~ first 64 KB of the second megabyte of memory;
* - Extended Memory: all the memory above first megabyte of memory.
* The high memory area overlaps with the first 64 KB of extended memory, but
* is different from the rest of extended memory because it can be accessed
* when the processor is in real mode.
*/
#define BASE_MEM_BEGIN 0x000000
#define BASE_MEM_TOP 0x090000
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#define BASE_MEM_END 0x09FFFF
#define UPPER_MEM_BEGIN 0x0A0000
#define UPPER_MEM_END 0x0FFFFF
#define HIGH_MEM_BEGIN 0x100000
#define HIGH_MEM_END 0x10FFEF
#define EXTENDED_MEM_BEGIN 0x100000
#define EXTENDED_MEM_END ((unsigned) -1)
/* The logical memory map of the first 1.5 MB is as follows (hexadecimals):
*
* offset [size] (id) = memory usage
* ------------------------------------------------------------------------
* 000000 [00400] (I) = Real-Mode Interrupt Vector Table (1024 B)
* 000400 [00100] (B) = BIOS Data Area (256 B)
* 000800 [00066] (W) = 80286 Loadall workspace
* 010000 [10000] (c) = Real-Mode Compatibility Segment (64 KB)
* 020000 [70000] (.) = Program-accessible memory (free)
* 090000 [10000] (E) = BIOS Extension
* 0A0000 [10000] (G) = Graphics Mode Video RAM
* 0B0000 [08000] (M) = Monochrome Text Mode Video RAM
* 0B8000 [08000] (C) = Color Text Mode Video RAM
* 0C0000 [08000] (V) = Video ROM BIOS (would be "a" in PS/2)
* 0C8000 [18000] (a) = Adapter ROM + special-purpose RAM (free UMA space)
* 0E0000 [10000] (r) = PS/2 Motherboard ROM BIOS (free UMA in non-PS/2)
* 0F0000 [06000] (R) = Motherboard ROM BIOS
* 0F6000 [08000] (b) = IBM Cassette BASIC ROM ("R" in IBM compatibles)
* 0FD000 [02000] (R) = Motherboard ROM BIOS
* 100000 [.....] (.) = Extended memory, program-accessible (free)
* 100000 [0FFEF] (h) = High Memory Area (HMA)
*
*
* Conventional (Base) Memory:
*
* : [~~~~~16 KB~~~~][~~~~~16 KB~~~~][~~~~~16 KB~~~~][~~~~~16 KB~~~~]
* : 0---1---2---3---4---5---6---7---8---9---A---B---C---D---E---F---
* 000000: IBW.............................................................
* 010000: cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc
* 020000: ................................................................
* 030000: ................................................................
* 040000: ................................................................
* 050000: ................................................................
* 060000: ................................................................
* 070000: ................................................................
* 080000: ................................................................
* 090000: EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE
*
* Upper Memory Area (UMA):
*
* : 0---1---2---3---4---5---6---7---8---9---A---B---C---D---E---F---
* 0A0000: GGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGG
* 0B0000: MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
* 0C0000: VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
* 0D0000: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
* 0E0000: rrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr
* 0F0000: RRRRRRRRRRRRRRRRRRRRRRRRbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbRRRRRRRR
*
* Extended Memory:
*
* : 0---1---2---3---4---5---6---7---8---9---A---B---C---D---E---F---
* 100000: hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh.
* 110000: ................................................................
* 120000: ................................................................
* 130000: ................................................................
* 140000: ................................................................
* 150000: ................................................................
* 160000: ................................................................
* 170000: ................................................................
*
* Source: The logical memory map was partly taken from the book "Upgrading
* & Repairing PCs Eight Edition", Macmillan Computer Publishing.
*/
/* The bottom part of conventional or base memory is occupied by BIOS data.
* The BIOS memory can be distinguished in two parts:
* o The first the first 1024 bytes of addressable memory contains the BIOS
* real-mode interrupt vector table (IVT). The table is used to access BIOS
* hardware services in real-mode by loading a interrupt vector and issuing
* an INT instruction. Some vectors contain BIOS data that can be retrieved
* directly and are useful in protected-mode as well.
* o The BIOS data area is located directly above the interrupt vectors. It
* comprises 256 bytes of memory. These data are used by the device drivers
* to retrieve hardware details, such as I/O ports to be used.
*/
#define BIOS_MEM_BEGIN 0x00000 /* all BIOS memory */
#define BIOS_MEM_END 0x004FF
#define BIOS_IVT_BEGIN 0x00000 /* BIOS interrupt vectors */
#define BIOS_IVT_END 0x003FF
#define BIOS_DATA_BEGIN 0x00400 /* BIOS data area */
#define BIOS_DATA_END 0x004FF
/* The base memory is followed by 384 KB reserved memory located at the top of
* the first MB of physical memory. This memory is known as the upper memory
* area (UMA). It is used for memory-mapped peripherals, such as video RAM,
* adapter BIOS (adapter ROM and special purpose RAM), and the motherboard
* BIOS (I/O system, Power-On Self Test, bootstrap loader). The upper memory
* can roughly be distinguished in three parts:
*
* o The first 128K of the upper memory area (A0000-BFFFF) is reserved for use
* by memory-mapped video adapters. Hence, it is also called Video RAM. The
* display driver can directly write to this memory and request the hardware
* to show the data on the screen.
*/
#define UMA_VIDEO_RAM_BEGIN 0xA0000 /* video RAM */
#define UMA_VIDEO_RAM_END 0xBFFFF
#define UMA_GRAPHICS_RAM_BEGIN 0xA0000 /* graphics RAM */
#define UMA_GRAPHICS_RAM_END 0xAFFFF
#define UMA_MONO_TEXT_BEGIN 0xB0000 /* monochrome text */
#define UMA_MONO_TEXT_END 0xB7FFF
#define UMA_COLOR_TEXT_BEGIN 0xB8000 /* color text */
#define UMA_COLOR_TEXT_END 0xBFFFF
/* o The next 128K (the memory range C0000-DFFFF) is reserved for the adapter
* BIOS that resides in the ROM on some adapter boards. Most VGA-compatible
* video adapters use the first 32 KB of this area for their on-board BIOS.
* The rest can be used by any other adapters. The IDE controller often
* occupies the second 32 KB.
*/
#define UMA_ADAPTER_BIOS_BEGIN 0xC0000 /* adapter BIOS */
#define UMA_ADAPTER_BIOS_END 0xDFFFF
#define UMA_VIDEO_BIOS_BEGIN 0xC0000 /* video adapter */
#define UMA_VIDEO_BIOS_END 0xC7FFF
#define UMA_IDE_HD_BIOS_BEGIN 0xC8000 /* IDE hard disk */
#define UMA_IDE_HD_BIOS_END 0xCBFFF
/* o The last 128K of the upper memory area (E0000-FFFFF) is reserved for
* motherboard BIOS (Basic I/O System). The POST (Power-On Self Test) and
* bootstrap loader also reside in this space. The memory falls apart in
* two areas: Plug & Play BIOS data and the system BIOS data.
*/
#define UMA_MB_BIOS_BEGIN 0xE0000 /* motherboard BIOS */
#define UMA_MB_BIOS_END 0xFFFFF
#define UMA_PNP_ESCD_BIOS_BEGIN 0xE0000 /* PnP extended data */
#define UMA_PNP_ESCD_BIOS_END 0xEFFFF
#define UMA_SYSTEM_BIOS_BEGIN 0xF0000 /* system BIOS */
#define UMA_SYSTEM_BIOS_END 0xFFFFF