## heap-tags.api
# Compiled by:
# src/lib/compiler/core.sublib# Abstract interface to the encoding of heapchunk tagwords.
#
# This is a Mythryl-level version of
#
# src/c/h/heap-tags.h
api Heap_Tags {
#
Btag;
tag_width: Int; # number of bits to hold a tag
pow_tag_width: Int; # 2 ^ tagWidth
max_length: Int; # one greater than max length value
# B-tag values:
#
pairs_and_records_btag: Btag;
ro_vector_header_btag: Btag;
rw_vector_header_btag: Btag;
rw_vector_data_btag: Btag;
four_byte_aligned_nonpointer_data_btag: Btag;
eight_byte_aligned_nonpointer_data_btag: Btag;
weak_pointer_or_suspension_btag: Btag;
#
ro_vector_data_btag: Btag; # Synonym for pairs_and_records_btag.
refcell_btag: Btag; # Synonym for rw_vector_data_btag.
# Build a tagword from a tag and length:
#
make_tagword: (Int, Btag) -> large_unt::Unt;
# Fixed descriptors:
#
pair_tagword: large_unt::Unt;
refcell_tagword: large_unt::Unt;
float64_tagword: large_unt::Unt;
typeagnostic_ro_vector_tagword: large_unt::Unt;
typeagnostic_rw_vector_tagword: large_unt::Unt;
weak_pointer_or_suspension_tagword: large_unt::Unt; # with 0 length
# Special descriptors stored in 'length' slots -- see src/c/h/heap-tags.h
#
evaluated_lazy_suspension_ctag: Int;
unevaluated_lazy_suspension_ctag: Int;
weak_pointer_ctag: Int;
nulled_weak_pointer_ctag: Int;
};
## COPYRIGHT (c) 1998 Bell Labs, Lucent Technologies.
## Subsequent changes by Jeff Prothero Copyright (c) 2010-2015,
## released per terms of SMLNJ-COPYRIGHT.