ack/mach/powerpc/libem/csa.s
George Koehler 26de4c1ab1 Add test for EM _rck_. Fix traps in PowerPC ncg.
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_.
2017-12-24 22:37:52 -05:00

34 lines
851 B
ArmAsm

.sect .text
! this is not a subroutine, but just a
! piece of code that computes the jump-
! address and jumps to it.
! traps if resulting address is zero
!
! Stack: ( value tableaddr -- )
.define .csa
.csa:
lwz r3, 0(sp)
lwz r4, 4(sp)
addi sp, sp, 8
lwz r5, 0(r3) ! r5 = default target
lwz r6, 4(r3) ! fetch lower bound
subf. r4, r6, r4 ! adjust value
blt 1f ! jump to default if out of range
lwz r6, 8(r3) ! fetch range
cmplw r4, r6
bgt 1f ! jump to default if out of range
addi r3, r3, 12 ! skip header
slwi r4, r4, 2 ! scale value (<<2)
lwzx r5, r3, r4 ! r5 = new target
1: mtspr ctr, r5
mr. r5, r5 ! test it
bnectr ! jump to target if non-zero
b .trap_ecase ! otherwise trap