mirror of
https://sourceware.org/git/binutils-gdb.git
synced 2026-08-27 00:26:02 -04:00
Fix "bins" simulation for v850e3v5
I've been carrying this for a few years. One test in the GCC testsuite is failing due to a bug in the handling of the v850e3v5 instruction "bins". When the "bins" instruction specifies a 32bit bitfield size, the simulator exhibits undefined behavior by trying to shift a 32 bit quantity by 32 bits. In the case of a 32 bit shift, we know what the resultant mask should be. So we can just set it. That seemed better than using 1UL for the constant (on a 32bit host unsigned long might still just be 32 bits) or needlessly forcing everything to long long types. Thankfully the case where this shows up is only bins <src>, 0, 32, <dest> which would normally be encoded as a simple move. * testsuite/v850/allinsns.exp: Add v850e3v5. * testsuite/v850/bins.cgs: New test. * v850/simops.c (v850_bins): Avoid undefined behavior on left shift.
This commit is contained in:
parent
7fb56b9893
commit
49fffa58f7
3 changed files with 21 additions and 2 deletions
|
|
@ -5,7 +5,7 @@ sim_init
|
|||
# All machines.
|
||||
# Should add more cpus if the testsuite adds coverage for their insns, but
|
||||
# at the core level, there's no deviation beyond these two.
|
||||
set all_machs "v850e v850"
|
||||
set all_machs "v850e3v5 v850e v850"
|
||||
|
||||
# gas doesn't support any '=' option for v850.
|
||||
set cpu_option_sep ""
|
||||
|
|
|
|||
12
sim/testsuite/v850/bins.cgs
Normal file
12
sim/testsuite/v850/bins.cgs
Normal file
|
|
@ -0,0 +1,12 @@
|
|||
# v850 bins
|
||||
# mach: v850e3v5
|
||||
# as: -mv850e3v5
|
||||
|
||||
.include "testutils.inc"
|
||||
|
||||
seti 0x7fff, r10
|
||||
seti 0x0, r11
|
||||
bins r10, 0, 32, r11
|
||||
reg r11, 0x7fff
|
||||
|
||||
pass
|
||||
|
|
@ -3267,7 +3267,14 @@ v850_bins (SIM_DESC sd, unsigned int source, unsigned int lsb, unsigned int msb,
|
|||
pos = lsb;
|
||||
width = (msb - lsb) + 1;
|
||||
|
||||
mask = ~ (-(1 << width));
|
||||
/* A width of 32 exhibits undefined behavior on the shift. The easiest
|
||||
way to make this code safe is to just avoid that case and set the mask
|
||||
to the right value. */
|
||||
if (width >= 32)
|
||||
mask = 0xffffffff;
|
||||
else
|
||||
mask = ~ (-(1 << width));
|
||||
|
||||
source &= mask;
|
||||
mask <<= pos;
|
||||
result = (* dest) & ~ mask;
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue