Fcalva/cyclone
1
0
Fork 0
mirror of https://github.com/justinethier/cyclone.git synced 2025-07-12 15:27:36 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions

Value type docs

Browse source
This commit is contained in:
Justin Ethier 2017-02-23 21:12:33 -05:00
parent 0acd61e9be
commit 27b77daa87
1 changed files with 44 additions and 9 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

53
include/cyclone/types.h
View file

@ -80,7 +80,8 @@
typedef void *object;
/**
* Define a tag for each possible type of object.
* Define a unique tag for each possible type of object.
*
* Remember to update tag_names in runtime.c when adding new tags
*\ingroup objects
*/
@ -260,31 +261,65 @@ struct gc_thread_data_t {
/**
* \defgroup immediates Value Types
*/
/**@{*/
/** Define value types.
*
* Value types (also known as immediates) are stored directly within
* the bits that would otherwise be a pointer to an object type. Since
* all of the data is contained in those bits, a value type is never
* allocated on the heap and never needs to be garbage collected,
* making them very efficient.
*
* Depending on the underlying architecture, compiler, etc these types
* have extra least significant bits that can be used to mark them as
* values instead of objects (IE, pointer to a tagged object).
* On many machines, addresses are multiples of four, leaving the two
* least significant bits free - from lisp in small pieces.
*
* Types:
* 0x00 - pointer (an object type)
* 0x01 - integer (in progress)
* 0x10 - char
* The possible types are:
*
* - 0x00 - pointer (an object type)
* - 0x01 - integer
* - 0x10 - char
*/
/**@{*/
/**
* Determine if an object is an integer.
*/
#define obj_is_int(x) ((unsigned long)(x) & (unsigned long)1)
/**
* Convert from an object to an integer.
*/
#define obj_obj2int(x) ((long)(x)>>1)
/**
* Convert from an integer to an object.
*/
#define obj_int2obj(c) ((void *)((((long)c)<<1) | 1))
/**
* Determine if the object is a char.
*/
#define obj_is_char(x) (((unsigned long)(x) & (unsigned long)3) == 2)
/**
* Convert from an object to a char.
*/
#define obj_obj2char(x) (char)((long)(x)>>2)
/**
* Convert from a char to an object.
*/
#define obj_char2obj(c) ((void *)((((unsigned long)c)<<2) | 2))
/**
* Is the given object a value type?
*/
#define is_value_type(x) ((unsigned long)(x) & (unsigned long)3)
/**
* Is the given object an object (non-immediate) type?
*/
#define is_object_type(x) (x && !is_value_type(x))
/**@}*/