Shifts that drop an EM word don't need to coerce the word to REG.
Some arithmetic right shifts can use _cdq_.
Drop rules for illegal integer conversions. Sizes below a word are
illegal in EM, except as the source size of _cii_.
Add EXACT to the rule for adi 8, in the same way that the old rules
for and 8, ior 8, xor 8 have EXACT.
Add rules for sli 8 and sru 8 when shifting 32 bits, and add
assertions in llshift_e.c to test these rules.
My i386 code from 893df4b gave the wrong sign to some 8-byte
remainders. Fix by splitting .dvi8 and .rmi8 so each has its own code
to pick the sign. They and .dvu8 and .rmu8 share a private sub
.divrem8 for unsigned division.
Improve the i386 code by using instructions like _bsr_ and _shrd_.
Change the helpers to yield a quotient in ebx:eax or a remainder in
ecx:edx; this seems more convenient, because _div_ puts its quotient
in eax and remainder in edx.
Add tests for comparisons and shifts. Also add enough integer
conversions to compile the shift test (llshift_e.c), and disable
some wrong rules for ldc and conversions.
This provides adi, sbi, mli, dvi, rmi, ngi, dvu, rmu 8, but is missing
shifts and rotates. It is also missing conversions between 8-byte
integers and other sizes of integers or floats. The code might not be
all correct, but works at least some of the time.
I adapted this from how ncg i86 does 4-byte integers, but I use a
different algorithm when dividing by a large value: i86 avoids the div
instruction and uses a shift-and-subtract loop; but I use the div
instruction to estimate a quotient, which is more like how big integer
libraries do division. My .dvi8 and .dvu8 also set ecx:ebx to the
remainder; this might be a bad idea, because it requires .dvi8 and
.dvu8 to always calculate the remainder, even when the caller only
wants the quotient.
To play with 8-byte integers, I wrote EM procedures like
mes 2, 4, 4
exp $ngi
pro $ngi,0
ldl 4
ngi 8
lol 0
sti 8
lol 0
ret 4
end
exp $adi
pro $adi,0
ldl 4
ldl 12
adi 8
lol 0
sti 8
lol 0
ret 4
end
and called them from C like
typedef struct { int l; int h; } q;
q ngi(q);
q adi(q, q);
This turns EM `con 5000000000I8` into assembly `.data8 5000000000` for
machines i386, i80, i86, m68020, powerpc, vc4. These are the only ncg
machines in our build.
i80 and i86 get con_mult(sz) for sz == 4 and sz == 8. The other
machines only get sz == 8, because they have 4-byte words, and ncg
only calls con_mult(sz) when sz is greater than the word size. The
tab "\t" after .data4 or .data8 is like the tabs in the con_*() macros
of mach/*/ncg/mach.h.
i86 now uses .data4, like i80. Also, i86 and i386 now use the numeric
string without converting it to an integer and back to a string.
gcc gave an error because the `char *` parameter doesn't match the
`const char *` in the prototype of regsave(). clang didn't give an
error. I added the prototype in commit 5301cce.
This breaks all machines because the declared return type void
disagrees with the implicit return type int (when I compile mach.c
with clang). Unbreak i386, i80, i86, m68020, powerpc, vc4 by adding
the return types to mach.c. We don't build any other machines; they
are broken since commit a46ee91 (May 19, 2013) declared void prolog()
and commit fd91851 (Nov 10, 2016) declared void mes(), with both
declarations in mach/proto/ncg/fillem.c.
Also fix mach/vc4/ncg/mach.c where type full is long, so fprintf()
must use "%ld" not "%d" to print full nlocals.
These files "magically reappeared" after the conversion from CVS to
Mercurial. The old CVS repository deleted these files but did not
record *when* it deleted these files. The conversion resurrected these
files because they have no history of deletion. These files were
probably deleted before year 1995. The CVS repository begins to record
deletions around 1995.
These files may still appear in older revisions of this Mercurial
repository, when they should already be deleted. There is no way to fix
this, because the CVS repository provides no dates of deletion.
See http://sourceforge.net/mailarchive/message.php?msg_id=29823032
