# op\_offset

Convert operand to a complex offset expression This is a more powerful version of [op\_plain\_offset](/8.4/developer-guide/idc/idc-api-reference/alphabetical-list-of-idc-functions/697.md)() function. It allows to explicitly specify the reference type (off8, off16, etc) and the expression target with a possible target delta. The complex expressions are represented by IDA in the following form:

```
        target + tdelta - base
```

If the target is not present, then it will be calculated using target = operand\_value - tdelta + base The target must be present for LOW\.. and HIGH.. reference types ea - linear address of the instruction/data n - number of operand to convert (the same as in op\_plain\_offset) reftype - one of REF\_... constants target - an explicitly specified expression target. if you don't want to specify it, use -1. Please note that LOW\... and HIGH... reference type require the target. base - the offset base (a linear address) tdelta - a displacement from the target which will be displayed in the expression.

success op\_offset(long ea, int n, long reftype, long target, long base, long tdelta);

\#define REF\_OFF8 0 // 8bit full offset #define REF\_OFF16 1 // 16bit full offset #define REF\_OFF32 2 // 32bit full offset #define REF\_LOW8 3 // low 8bits of 16bit offset #define REF\_LOW16 4 // low 16bits of 32bit offset #define REF\_HIGH8 5 // high 8bits of 16bit offset #define REF\_HIGH16 6 // high 16bits of 32bit offset #define V695\_REF\_VHIGH 7 // obsolete #define V695\_REF\_VLOW 8 // obsolete #define REF\_OFF64 9 // 64bit full offset // note: processor modules or plugins may register additional // custom reference types (for example, REF\_HIGHA16 is // used by MIPS, SPARC, PPC, ALPHA, TRICORE, etc.) #define REFINFO\_RVA 0x10 // based reference (rva) #define REFINFO\_PASTEND 0x20 // reference past an item // it may point to an nonexistitng address // do not destroy alignment dirs #define REFINFO\_NOBASE 0x80 // offset base is a number // implies that base have be any value // nb: base xrefs are created only if base // points to the middle of a segment #define REFINFO\_SUBTRACT 0x0100 // the reference value is subtracted from // the base value instead of (as usual) // being added to it #define REFINFO\_SIGNEDOP 0x0200 // the operand value is sign-extended (only // supported for REF\_OFF8/16/32/64) #define REFINFO\_NO\_ZEROS 0x0400 ///< an opval of 0 will be considered invalid #define REFINFO\_NO\_ONES 0x0800 ///< an opval of \~0 will be considered invalid


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