#1251: handle ARM mixed-endian doubles
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Reporter: jkeenan | Owner:
Type: todo | Status: new
Priority: normal | Milestone:
Component: core | Version: 1.7.0
Severity: medium | Keywords:
Lang: | Patch:
Platform: |
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This ticket moves discussion into Trac from
[http://rt.perl.org/rt3/Ticket/Display.html?id=37461 RT #37461].
Leopold Toetsch opened the ticket in October 2005:
Parrot bytecode (PBC) is designed to be portable. Therefore we need
some code to convert ARM-generated PBCs to machine-native doubles and
ARM architectures must be able to read other already supported float
types.
A PBC header has a 'floattype' field, which identifies known FLOATVAL
layouts.
We have currently:
0 ... 8 byte IEEE double
1 ... 12 byte IEEE double (both according to endianess)
We need additionally (at least and AFAIK):
2 ... 8 byte (ARM) mixed-endian
which is according to Nicholas a LE double with 2 BE arranged words.
And Nicholas Clark commented:
and totally legal IEEE.
(Mozilla thought that it could cheat. And it was wrong)
The mixed endian is the old soft float, as I understand it, and will be
replaced by something less surprising, but that's a C ABI change.
... and that's where things stand.
--
Ticket URL: <https://trac.parrot.org/parrot/ticket/1251>
Parrot <https://trac.parrot.org/parrot/>
Parrot Development
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