The new test rck_e.e segfaults on PowerPC unless I make some changes.
The inline code for _rck_ was wrong because it didn't allow the trap
handler to return. _sig_ forgot to push the old trap handler.
Move plat/linuxppc/libsys/trap.s to mach/powerpc/libem/trp.s and
rewrite it with simplified/extended mnemonics. Remove .trap alias for
.trp procedure. Add a missing `mtspr lr, r0` so we can return from
the trap handler. Call write() and _exit() so trp.s works with both
linuxppc and osxppc. Before, Mac OS X was wrongly using the trap.s
for Linux.
In powerpc/libem, simplify .aar4; teach .csa and .csb to raise the
trap if the default target is zero.
C programs don't need these changes. You may relink your C programs
with the changed .csa and .csb, but C code doesn't raise the trap.
Modula-2 code can raise traps, so you may want to relink your Modula-2
programs with the changed libem, but you might keep your old .o files
from Modula-2. You may need to recompile your Pascal programs (delete
old .o files from Pascal) because the Pascal compiler might use _rck_.
The new features are the hi16/lo16 and ha16/lo16 syntax for
relocations, and the extended mnemonics like "blr".
Use ha16/lo16 to load some double floats with 2 instructions (lis/lfd)
instead of 3 (lis/ori/lfd).
Use the extended names for branches, comparisons, and bit rotations,
so I can more easily read the code. The new names often encode the
same machine instructions as the old names, except in a few places
where I changed the instructions.
Stop using andi. when we don't need to set cr0. In inn.s, I change
andi. to extrwi to extract the same bits. In los.s and sts.s, I
change "andi. r3, r3, ~3" to "clrrwi r3, r3, 2". This avoids setting
cr0 and also stops clearing the high 16 bits of r3.
In csa.s, los.s, sts.s, I change some comparisons and right shifts
from signed to unsigned (cmplw, cmplwi, srwi), because the sizes are
unsigned. In inn.s, the right shift can be signed (sraw) or unsigned
(srw), but I use srw because we don't need the carry bit.
In fef8.s, I save an instruction by using rlwinm instead of addis/andc
to rlwinm to clear a field. The code no longer kills r7. In both
fef8.s and fif8.s, I remove the list of killed registers.
Also remove some whitespace from ends of lines.
corresponding invocation in the ncg table so the same helpers can be used for
both mcg and ncg. Add a new IR opcode, FARJUMP, which jumps to a helper
function but saves volatile registers.
