Muq Vm_Obj variables are basically 32-bit unsigneds, which can be used to refer to any user-visible object in the system: They are the basic type manipulated by a MUF programmer.
Muq Vm_Obj values store the types of certain (small) datatypes within the pointer itself. In fact, they store the values of certain (smaller!) datatypes within the pointer itself, also.
We interpret the meaning of a Vm_Obj by examining
the least significant eleven bits. Those with five-bit
tags are pointers into the virtual memory pool; The
remainder are immediate values stored in the pointer
itself, except for the ephemeral values, which are
offsets into some loop stack:
Bit: A9876543210 Meaning ----------- --------------------------------------------- *********00 62-bit int in upper 62 bits. *********10 Reserved for immediate complex values. ******11111 59-bit float in upper 59 bits. ******11101 Bignum ******11011 Struct (also CLOS objects and bignums). ******11001 Thunk/promise. ******10111 Procedure. ******10101 Standard obj stored in vm_obj. ******10011 CONS cell. ******10001 Symbol. ******01111 Vector. ******01101 Doublevector ******01011 Floatvector ******01001 Intvector ******00111 Shortvector. ******00101 Bytevector. (String.) ******00011 Bitvector. #ifdef OLD ***11100001 A 0-byte byte string. ***11000001 A 1-byte byte string (o >> 24) ***10100001 A 2-byte byte string (o >> 24), (o >> 16) ***10000001 A 3-byte byte string (o >> 24), (o >> 16), (o >> 8) #else 00011100001 A 0-byte byte string. 00111100001 A 1-byte byte string. 01011100001 A 2-byte byte string. ***11000001 A 3-byte byte string 10011100001 A 4-byte byte string. 10111100001 A 5-byte byte string. 11011100001 A 6-byte byte string. ***10100001 A 7-byte byte string. ***10000001 Unused (RBGA values?) #endif xxx01100001 Reserved for nonzero xxx. 00001100001 Bottom-of-stack value. 1**01000001 Reserved for future ephemeral types. 01101000001 Ephemeral (stack-allocated) vectors. 01001000001 Ephemeral (stack-allocated) structs. 00101000001 Ephemeral (stack-allocated) objects. 00001000001 Special values such as OBJ_NOT_FOUND. xxx00100001 Reserved for nonzero xxx. 00000100001 Top-of-block value. ***00000001 Char.
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