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{
$Id: simlib.pas,v 1.1 1999/06/14 11:49:48 florian Exp $
This file is part of the Free Pascal simulator environment
Copyright (c) 1999 by Florian Klaempfl
This unit implemements routines for data types which aren't
support by commonly used compilers
See the file COPYING.FPC, included in this distribution,
for details about the copyright.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
**********************************************************************}
{$N+}
{ we do some strange things here }
{$O-}
{$R-}
unit simlib;
interface
uses
simbase;
procedure byte_zap(q : qword;b : byte;var result : qword);
{ shifts q b bytes left }
procedure shift_left_q(q : qword;b : byte;var result : qword);
{ shifts q b bytes right }
procedure shift_right_q(q : qword;b : byte;var result : qword);
{ returns true if i1<i2 assuming that c1 and c2 are unsigned !}
function ltu(c1,c2 : comp) : boolean;
{ returns true if i1=<i2 assuming that c1 and c2 are unsigned !}
function leu(c1,c2 : comp) : boolean;
{ adds to owords, returns true if an overflow occurs }
function addoword(o1,o2 : oword;var result : oword) : boolean;
{ adds two words, returns true if an overflow occurs }
function addword(w1,w2 : word;var result : word) : boolean;
{ sets an oword to zero }
procedure zerooword(var o : oword);
{ multiplies two qwords into a full oword }
procedure mulqword(q1,q2 : qword;var result : oword);
implementation
procedure byte_zap(q : qword;b : byte;var result : qword);
var
i : tindex;
begin
for i:=0 to 7 do
if ((1 shl i) and b)=0 then
tqwordrec(result).bytes[i]:=tqwordrec(q).bytes[i]
else
tqwordrec(result).bytes[i]:=0;
end;
{ shifts q b bytes left }
procedure shift_left_q(q : qword;b : byte;var result : qword);
var
i : tindex;
begin
result:=0;
if b>63 then
else if b>31 then
tqwordrec(result).high32:=tqwordrec(q).low32 shl (b-32)
else
begin
{ bad solution! A qword shift would be nice! }
result:=q;
for i:=1 to b do
begin
tqwordrec(result).high32:=tqwordrec(result).high32 shl 1;
if (tqwordrec(result).low32 and $80000000)<>0 then
tqwordrec(result).high32:=tqwordrec(result).high32 or 1;
tqwordrec(result).low32:=tqwordrec(result).low32 shl 1;
end;
end;
end;
{ shifts q b bytes right }
procedure shift_right_q(q : qword;b : byte;var result : qword);
var
i : tindex;
begin
result:=0;
if b>63 then
else if b>31 then
tqwordrec(result).low32:=tqwordrec(q).high32 shr (b-32)
else
begin
{ bad solution! A qword shift would be nice! }
result:=q;
for i:=1 to b do
begin
tqwordrec(result).low32:=tqwordrec(result).low32 shr 1;
if (tqwordrec(result).high32 and 1)<>0 then
tqwordrec(result).low32:=tqwordrec(result).low32 or
$80000000;
tqwordrec(result).high32:=tqwordrec(result).high32 shr 1;
end;
end;
end;
{ returns true if i1<i2 assuming that c1 and c2 are unsigned !}
function ltu(c1,c2 : comp) : boolean;
begin
if (c1>=0) and (c2>=0) then
ltu:=c1<c2
else if (c1<0) and (c2>=0) then
ltu:=false
else if (c1>=0) and (c2<0) then
ltu:=true
else
ltu:=c1<c2
end;
{ returns true if i1=<i2 assuming that c1 and c2 are unsigned !}
function leu(c1,c2 : comp) : boolean;
begin
if (c1>=0) and (c2>=0) then
leu:=c1<=c2
else if (c1<0) and (c2>=0) then
leu:=false
else if (c1>=0) and (c2<0) then
leu:=true
else
leu:=c1<=c2
end;
{ "ands" two qwords }
procedure andqword(w1,w2 : qword;var result : qword);
begin
tqwordrec(result).low32:=tqwordrec(w1).low32 and tqwordrec(w2).low32;
tqwordrec(result).high32:=tqwordrec(w1).high32 and tqwordrec(w2).high32;
end;
{ adds two words, returns true if an overflow occurs }
function addword(w1,w2 : word;var result : word) : boolean;
var
l : longint;
begin
l:=w1+w2;
addword:=(l and $10000)<>0;
result:=l and $ffff;
end;
{ adds two owords, returns true if an overflow occurs }
function addoword(o1,o2 : oword;var result : oword) : boolean;
var
i : tindex;
carry : word;
begin
carry:=0;
for i:=0 to 7 do
begin
result[i]:=o1[i]+o2[i]+carry;
{ an overflow has occured, if the result is less
than one of the summands
}
if (result[i]<o1[i]) or (result[i]<o2[i]) then
carry:=1
else
carry:=0;
end;
addoword:=carry=1;
end;
{ sets an oword to zero }
procedure zerooword(var o : oword);
begin
fillchar(o,sizeof(o),0);
end;
{ multiplies two qwords into a full oword }
procedure mulqword(q1,q2 : qword;var result : oword);
var
i : tindex;
h,bitpos : qword;
ho1 : oword;
begin
{ result is zero }
zerooword(ho1);
result:=ho1;
towordrec(ho1).low64:=q1;
bitpos:=1;
for i:=0 to 63 do
begin
andqword(q2,bitpos,h);
if h<>0 then
addoword(result,ho1,result);
{ ho1:=2*ho1 }
addoword(ho1,ho1,ho1);
shift_left_q(bitpos,1,bitpos);
end;
end;
end.
{
$Log: simlib.pas,v $
Revision 1.1 1999/06/14 11:49:48 florian
+ initial revision, it runs simple Alpha Linux ELF executables
- integer operations are nearly completed (non with overflow checking)
- floating point operations aren't implemented (except loading and
storing)
- only the really necessary system calls are implemented by dummys
write syscalls are redirected to the console
}
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