Microsoft File Types

SYM.md

Symbol file (.SYM)

Source: https://git.ignuranza.net/Microsoft/WindowsXP-SP1/src/branch/master/sdktools/mapsym/mapsym.h

Hierarchy

• File (e.g. USER.SYM)
  • Map
    • Constant (Absolute symbol)
    • Segment
      • Symbol
      • Line
        • Record
  • End Map

Structs

Map Definition Struct

Struct name: mapdef_s

Field	Type	Name	Description	Comment
md_spmap	unsigned short (2)	S Pointer Map	Pointer to next map or zero if end	/* 16 bit SEG ptr to next map (0 if end) */
md_abstype	unsigned char (1)	Absolutes type	Type of absolute symbols	/* 8 bit map/abs sym flags */
md_pad	unsigned char (1)	Padding	Seems to be always zero	/* 8 bit pad */
md_segentry	unsigned short (2)	Segment Entry	Entry point	/* 16 bit entry point segment value */
md_cabs	unsigned short (2)	Count Absolutes	Amount of absolute symbols	/* 16 bit count of constants in map */
md_pabsoff	unsigned short (2)	Pointer Absolutes Offset	Pointer offset to absolute symbols	/* 16 bit ptr to constant offsets */
md_cseg	unsigned short (2)	Count Segment	Amount of segments	/* 16 bit count of segments in map */
md_spseg	unsigned short (2)	S Pointer Segment	Pointer to segments	/* 16 bit SEG ptr to segment chain */
md_cbnamemax	unsigned char (1)	Count Name Maximum	Maximum name length	/* 8 bit maximum symbol name length */
md_cbname	unsigned char (1)	Count Byte Name	Length of name	/* 8 bit symbol table name length */
md_achname	unsigned char[] (*)	ASCII Character Name	The name of the map	/* <n> name of symbol table (.sym ) */

End Map Struct

Struct name: endmap_s

Field	Type	Name	Description	Comment
em_spmap	unsigned short (2)	S Pointer Map	Pointer to next map or zero if end	/* end of map chain (SEG ptr 0) */
em_rel	unsigned char (1)	Release	Release (minor) of the MapSym executable	/* release */
em_ver	unsigned char (1)	Version	Version (major) of the MapSym executable	/* version */

Segment/Group Definition Struct

Struct name: segdef_s

Field	Type	Name	Description	Comment
gd_spsegnext	unsigned short (2)	S Pointer Segment Next	Pointer to next segment	/* 16 bit SEG ptr to next segdef (0 if end), relative to mapdef */
gd_csym	unsigned short (2)	Count Symbols	Amount of symbols	/* 16 bit count of symbols in sym list */
gd_psymoff	unsigned short (2)	Pointer Symbols Offset	Pointer offset to symbols	/* 16 bit ptr to symbol offsets array, 16 bit SEG ptr if MSF_BIG_GROUP set, either relative to segdef */
gd_lsa	unsigned short (2)	Load Segment Address	...	/* 16 bit Load Segment address */
gd_in0	unsigned short (2)	Instance 0	...	/* 16 bit instance 0 physical address */
gd_in1	unsigned short (2)	Instance 1	...	/* 16 bit instance 1 physical address */
gd_in2	unsigned short (2)	Instance 2	...	/* 16 bit instance 2 physical address */
gd_type	unsigned char (1)	Type	Type flags	/* 16 or 32 bit symbols in group */
gd_pad	unsigned char (1)	Padding	...	/* pad byte to fill space for gd_in3 */
gd_spline	unsigned short (2)	S Pointer Line	Pointer to lines	/* 16 bit SEG ptr to linedef, relative to mapdef */
gd_fload	unsigned char (1)	F Load	...	/* 8 bit boolean 0 if seg not loaded */
gd_curin	unsigned char (1)	Current Instance	...	/* 8 bit current instance */
gd_cbname	unsigned char (1)	Count Byte Name	Length of name	/* 8 bit Segment name length */
gd_achname	unsigned char[] (*)	ASCII Character Name	The name of the segment	/* <n> name of segment or group */

Symbol Definition 16 Struct

Struct name: symdef16_s

Field	Type	Name	Description	Comment
sd16_val	unsigned short (2)	Value	Address value or constant value	/* 16 bit symbol addr or const */
sd16_cbname	unsigned char (1)	Count Byte Name	Length of name	/* 8 bit symbol name length */
sd16_achname	unsigned char[] (*)	ASCII Character Name	Name of symbol	/* <n> symbol name */

Symbol Definition 32 Struct

Struct name: symdef_s

Field	Type	Name	Description	Comment
sd_lval	unsigned long (4)	Long Value	Address value or constant value	/* 32 bit symbol addr or const */
sd_cbname	unsigned char (1)	Count Byte Name	Length of name	/* 8 bit symbol name length */
sd_achname	unsigned char[] (*)	ASCII Character Name	Name of symbol	/* <n> symbol name */

Line Definition Struct

Struct name: linedef_s

Field	Type	Name	Description	Comment
ld_splinenext	unsigned short (2)	S Pointer Line Next	Pointer to next line	/* 16 bit SEG ptr to next (0 if last), relative to mapdef */
ld_pseg	unsigned short (2)	Pointer Segment	Always zero	/* 16 bit ptr to segdef_s (always 0) */
ld_plinerec	unsigned short (2)	Pointer Line record	Pointer to line records	/* 16 bit ptr to linerecs, relative to linedef */
ld_itype	unsigned short (2)	Integer Type	Type of line record	/* line rec type 0, 1, or 2 */
ld_cline	unsigned short (2)	Count Line	Amount of lines	/* 16 bit count of line numbers */
ld_cbname	unsigned char (1)	Count Byte Name	Length of name	/* 8 bit file name length */
ld_achname	unsigned char[] (*)	ASCII Character Name	Name of file	/* <n> file name */

Line Record 0 Struct

Struct name: linerec0_s

Field	Type	Name	Description	Comment
lr0_codeoffset	unsigned short (2)	Code Offset	Code offset	/* start offset for this linenumber */
lr0_fileoffset	unsigned long (4)	File Offset	File offset	/* file offset for this linenumber */

Line Record 1 Struct

Struct name: linerec1_s

Field	Type	Name	Description	Comment
lr1_codeoffset	unsigned short (2)	Code Offset	Code offset	/* start offset for this linenumber */
lr1_linenumber	unsigned short (2)	Line Number	Line number	/* linenumber */

Line Record 2 Struct

Struct name: linerec2_s

Field	Type	Name	Description	Comment
lr2_codeoffset	unsigned long (4)	Code Offset	Code offset	/* start offset for this linenumber */
lr2_linenumber	unsigned short (2)	Line Number	Line number	/* linenumber */