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ld_assign: cleanups

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Mikael Pettersson
2023-08-13 18:57:21 +02:00
parent fbb8276b11
commit b4ec2ef819
1 changed files with 19 additions and 11 deletions
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30
erlang/apps/ld/src/ld_assign.erl
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@@ -1,7 +1,7 @@
%%% -*- erlang-indent-level: 2 -*-
%%%
%%% Assigning addresses for pdp10-elf-ld
%%% Copyright (C) 2020 Mikael Pettersson
%%% Assigning addresses for pdp10-elf ld
%%% Copyright (C) 2020-2023 Mikael Pettersson
%%%
%%% This file is part of pdp10-tools.
%%%
@@ -17,6 +17,11 @@
%%%
%%% You should have received a copy of the GNU General Public License
%%% along with pdp10-tools. If not, see <http://www.gnu.org/licenses/>.
%%%
%%%=============================================================================
%%%
%%% Finalize the Phdrs for the PT_LOAD segments by assigning virtual addresses
%%% and segment offsets.
-module(ld_assign).
@@ -25,24 +30,27 @@
-include("ld_internal.hrl").
%% Output ======================================================================
%% Assign addresses and offsets to PT_LOAD segments ============================
-spec assign([#segment{}]) -> [#segment{}].
assign(Segments) ->
%% TODO: assumes KL10B-compatible "small" code model output
VAddr = 8#00001001000 bsl 2, % section 1, page 1
PhNum = length(Segments),
true = PhNum < ?PN_XNUM, % assert; TODO: otherwise store PhNum in Shdr0.sh_info
%% TODO: assumes KL10B-compatible "small" code model output
VAddr = 8#00001001000 bsl 2, % section 1, page 1, word address to byte address
Offset = ?ELF36_EHDR_SIZEOF + ?ELF36_PHDR_SIZEOF * PhNum,
assign(Segments, Offset, VAddr, []).
{_Offset, _VAddr, NewSegments} = lists:foldl(fun assign/2, {Offset, VAddr, []}, Segments),
lists:reverse(NewSegments).
assign(_Segments = [], _Offset, _VAddr, NewSegments) -> lists:reverse(NewSegments);
assign([Segment | Segments], Offset, VAddr, NewSegments) ->
assign(Segment, {Offset, VAddr, NewSegments}) ->
#segment{phdr = Phdr} = Segment,
#elf36_Phdr{p_filesz = FileSz, p_memsz = MemSz, p_align = Align} = Phdr,
SegAlign = max(4096, Align), % align to page boundary; TODO: target-specific
SegOffset = (Offset + (SegAlign - 1)) band bnot (SegAlign - 1),
SegVAddr = (VAddr + (SegAlign - 1)) band bnot (SegAlign - 1),
SegOffset = align(Offset, SegAlign),
SegVAddr = align(VAddr, SegAlign),
NewPhdr = Phdr#elf36_Phdr{p_offset = SegOffset, p_vaddr = SegVAddr, p_align = SegAlign},
NewSegment = Segment#segment{phdr = NewPhdr},
assign(Segments, SegOffset + FileSz, SegVAddr + MemSz, [NewSegment | NewSegments]).
{SegOffset + FileSz, SegVAddr + MemSz, [NewSegment | NewSegments]}.
align(Offset, Alignment) ->
(Offset + (Alignment - 1)) band bnot (Alignment - 1).