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Annotation of coherent/a/usr/man/ALL/address, revision 1.1

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        !             2: 
        !             3: address                     Definition                    address
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        !             8: An address  is the location  where an item  of data is  stored in
        !             9: memory.
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        !            11: On the  i8086, a physical address is a  20-bit number.  The i8086
        !            12: builds an  address by left-shifting  a 16-bit segment  address by
        !            13: four bits,  and then adding  it to a 16-bit  offset address.  The
        !            14: segment  address points  to a  particular  chunk of  memory.  The
        !            15: i8086 uses  four segment registers, each of  which governs a dif-
        !            16: ferent portion of a program, as follows:
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        !            19:              CS      Address of code segment
        !            20:              DS      Address of data segment
        !            21:              ES      Address of ``extra'' segment
        !            22:              SS      Address of stack segment
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        !            25: SMALL-model programs  use only  the offset address;  hence, their
        !            26: pointers are  only 16  bits long,  equivalent to an  iinntt.  LARGE-
        !            27: model programs use  both segment and offset addresses.  Their ad-
        !            28: dresses  are 20  bits  long, which  must  be stored  in a  32-bit
        !            29: pointer, equivalent to a lloonngg.  COHERENT currently supports SMALL
        !            30: model.
        !            31: 
        !            32: On  the M68000,  an address  is simply a  24-bit integer  that is
        !            33: stored as  a 32-bit integer.   The upper eight  bits are ignored;
        !            34: this is  not true with the more  advanced microprocessors in this
        !            35: family,  such as  the M68020.  The  M68000 uses  no segmentation;
        !            36: memory is organized as a ``flat address space'', with no restric-
        !            37: tions set on the size of code or data.
        !            38: 
        !            39: On machines  with memory-mapped I/O, such as  the 68000, some ad-
        !            40: dresses  may be  used to control  or communicate  with peripheral
        !            41: devices.
        !            42: 
        !            43: ***** Example *****
        !            44: 
        !            45: The following printes the address and contents of a given byte of
        !            46: memory.
        !            47: 
        !            48: 
        !            49: #include <stdio.h>
        !            50: 
        !            51: main()
        !            52: {
        !            53:         char byte = 'a';
        !            54:         printf("Address == %x\tContents == \"%c\"\n",
        !            55:                 &byte, byte);
        !            56: }
        !            57: 
        !            58: 
        !            59: ***** See Also *****
        !            60: 
        !            61: data formats, definitions, pointer
        !            62: 
        !            63: 
        !            64: COHERENT Lexicon                                           Page 1
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        !            68: 
        !            69: address                     Definition                    address
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        !            74: ***** Notes *****
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        !            76: COHERENT is in i8086 SMALL model; thus, its addresses are 16 bits
        !            77: long.
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        !           130: COHERENT Lexicon                                           Page 2
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