Fixup Record Table

The Fixup Record Table contains entries for all fixups in the linear EXE module. The fixup records for a logical page are grouped together and kept in sorted order by logical page number. The fixups for each page are further sorted such that all external fixups and internal selector/pointer fixups come before internal non-selector/non-pointer fixups. This allows the loader to ignore internal fixups if the loader is able to load all objects at the addresses specified in the object table. Each relocation record has the following format

          ﾚﾄﾄﾄﾄﾄﾂﾄﾄﾄﾄﾄﾂﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄｿ
      00h ｳ SRC ｳFLAGSｳSRCOFF/CNT*ｳ
          ﾃﾄﾄﾄﾄﾄﾁﾄﾄﾄﾄﾄﾁﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾁﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄｿ
  03h/04h ｳ           TARGET DATA *           ｳ
          ﾃﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾂﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾂﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄｴ
          ｳ SRCOFF1 @ ｳ   . . .   ｳ SRCOFFn @ ｳ
          ﾀﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾁﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾁﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾙ

        * These fields are variable size.
        @ These fields are optional.

Fixup Record Table

SRC = DB Source type. The source type specifies the size and type of the fixup to be performed on the fixup source. The source type is defined as follows

0Fh = Source mask.
00h = Byte fixup (8-bits).
01h = (undefined).
02h = 16-bit Selector fixup (16-bits).
03h = 16
04h = (undefined).
05h = 16-bit Offset fixup (16-bits).
06h = 16
07h = 32-bit Offset fixup (32-bits).
08h = 32-bit Self-relative offset fixup (32-bits).
10h = Fixup to Alias Flag. When the 'Fixup to Alias' Flag is set, the source fixup refers to the 16 This is only valid for source types of 2, 3, and 6. For fixups such as this, the linker and loader will be required to perform additional checks such as ensuring that the target offset for this fixup is less than 64K.

20h = Source List Flag. When the 'Source List' Flag is set, the SRCOFF field is compressed to a byte and contains the number of source offsets, and a list of source offsets follows the end of fixup record (after the optional additive value).

FLAGS = DB Target Flags. The target flags specify how the target information is interpreted. The target flags are defined as follows

03h = Fixup target type mask.
00h = Internal reference.
01h = Imported reference by ordinal.
02h = Imported reference by name.
03h = Internal reference via entry table.
04h = Additive Fixup Flag. When set, an additive value trails the fixup record (before the optional source offset list).

08h = Reserved. Must be zero.
10h = 32-bit Target Offset Flag. When set, the target offset is 32-bits, otherwise it is 16-bits.

20h = 32-bit Additive Fixup Flag. When set, the additive value is 32-bits, otherwise it is 16-bits.

40h = 16-bit Object Number/Module Ordinal Flag. When set, the object number or module ordinal number is 16-bits, otherwise it is 8-bits.

80h = 8-bit Ordinal Flag. When set, the ordinal number is 8-bits, otherwise it is 16-bits.

SRCOFF = DW/CNT = DB Source offset or source offset list count. This field contains either an offset or a count depending on the Source List Flag. If the Source List Flag is set, a list of source offsets follows the additive field and this field contains the count of the entries in the source offset list. Otherwise, this is the single source offset for the fixup. Source offsets are relative to the beginning of the page where the fixup is to be made. Note that for fixups that cross page boundaries, a separate fixup record is specified for each page. An offset is still used for the 2nd page but it now becomes a negative offset since the fixup originated on the preceding page. (For example, if only the last one byte of a 32-bit address is on the page to be fixed up, then the offset would have a value of -3.)

TARGET DATA = Target data for fixup. The format of the TARGET DATA is dependent upon target flags.

SRCOFF1 - SRCOFFn = DW[] Source offset list. This list is present if the Source List Flag is set in the Target Flags field. The number of entries in the source offset list is defined in the SRCOFF/CNT field. The source offsets are relative to the beginning of the page where the fixups are to be made.

          ﾚﾄﾄﾄﾄﾄﾂﾄﾄﾄﾄﾄﾂﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄｿ
      00h ｳ SRC ｳFLAGSｳSRCOFF/CNT*ｳ
          ﾃﾄﾄﾄﾄﾄﾁﾄﾄﾄﾄﾄﾅﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾁﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄｿ
  03h/04h ｳ  OBJECT * ｳ        TRGOFF * @     ｳ
          ﾃﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾅﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾂﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄｴ
          ｳ SRCOFF1 @ ｳ   . . .   ｳ SRCOFFn @ ｳ
          ﾀﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾁﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾁﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾙ

        * These fields are variable size.
        @ These fields are optional.

Internal Fixup Record

OBJECT = D[B|W] Target object number. This field is an index into the current module's Object Table to specify the target Object. It is a Byte value when the '16-bit Object Number/Module Ordinal Flag' bit in the target flags field is clear and a Word value when the bit is set.

TRGOFF = D[W|D] Target offset. This field is an offset into the specified target Object. It is not present when the Source Type specifies a 16-bit Selector fixup. It is a Word value when the '32-bit Target Offset Flag' bit in the target flags field is clear and a Dword value when the bit is set.

          ﾚﾄﾄﾄﾄﾄﾂﾄﾄﾄﾄﾄﾂﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄｿ

00h ｳ SRC ｳFLAGSｳSRCOFF/CNT*ｳﾃﾄﾄﾄﾄﾄﾁﾄﾄﾄﾄﾄﾅﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾁﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾂﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄｿ 03h/04h ｳ MOD ORD# *ｳ PROCEDURE NAME OFFSET*ｳ ADDITIVE * @ ｳﾃﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾅﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾂﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾅﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾙｳ SRCOFF1 @ ｳ . . . ｳ SRCOFFn @ ｳﾀﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾁﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾁﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾙ * These fields are variable size. @ These fields are optional.
Import by Name Fixup Record

MOD ORD # = D[B|W] Ordinal index into the Import Module Name Table. This value is an ordered index in to the Import Module Name Table for the module containing the procedure entry point. It is a Byte value when the '16-bit Object Number/Module Ordinal' Flag bit in the target flags field is clear and a Word value when the bit is set. The loader creates a table of pointers with each pointer in the table corresponds to the modules named in the Import Module Name Table. This value is used by the loader to index into this table created by the loader to locate the referenced module.

PROCEDURE NAME OFFSET = D[W|D] Offset into the Import Procedure Name Table. This field is an offset into the Import Procedure Name Table. It is a Word value when the '32-bit Target Offset Flag' bit in the target flags field is clear and a Dword value when the bit is set.

ADDITIVE = D[W|D] Additive fixup value. This field exists in the fixup record only when the 'Additive Fixup Flag' bit in the target flags field is set. When the 'Additive Fixup Flag' is clear the fixup record does not contain this field and is immediately followed by the next fixup record (or by the source offset list for this fixup record). This value is added to the address derived from the target entry point. This field is a Word value when the '32-bit Additive Flag' bit in the target flags field is clear and a Dword value when the bit is set.

          ﾚﾄﾄﾄﾄﾄﾂﾄﾄﾄﾄﾄﾂﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄｿ

00h ｳ SRC ｳFLAGSｳSRCOFF/CNT*ｳﾃﾄﾄﾄﾄﾄﾁﾄﾄﾄﾄﾄﾅﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾅﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄｿ 03h/04h ｳ MOD ORD# *ｳIMPORT ORD*ｳ ADDITIVE * @ ｳﾃﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾅﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾅﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾂﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾙｳ SRCOFF1 @ ｳ . . . ｳ SRCOFFn @ ｳﾀﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾁﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾁﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾙ * These fields are variable size. @ These fields are optional.
Import by Ordinal Fixup Record

IMPORT ORD = D[B|W|D] Imported ordinal number. This is the imported procedure's ordinal number. It is a Byte value when the '8-bit Ordinal' bit in the target flags field is set. Otherwise it is a Word value when the '32-bit Target Offset Flag' bit in the target flags field is clear and a Dword value when the bit is set.

          ﾚﾄﾄﾄﾄﾄﾂﾄﾄﾄﾄﾄﾂﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄｿ

00h ｳ SRC ｳFLAGSｳSRCOFF/CNT*ｳﾃﾄﾄﾄﾄﾄﾁﾄﾄﾄﾄﾄﾅﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾁﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄｿ 03h/04h ｳ ORD # * ｳ ADDITIVE * @ ｳﾃﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾅﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾂﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄｴｳ SRCOFF1 @ ｳ . . . ｳ SRCOFFn @ ｳﾀﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾁﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾁﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾙ * These fields are variable size. @ These fields are optional.
Internal Entry Table Fixup Record

ENTRY # = D[B|W] Ordinal index into the Entry Table. This field is an index into the current module's Entry Table to specify the target Object and offset. It is a Byte value when the '16-bit Object Number/Module Ordinal' Flag bit in the target flags field is clear and a Word value when the bit is set.

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