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authorLaurent Vivier <laurent@vivier.eu>2017-06-14 22:39:05 +0200
committerLaurent Vivier <laurent@vivier.eu>2017-06-15 08:50:30 +0200
commit043b936ef6fe53396b3c6b8f5562ea3e238a071d (patch)
treed50b1901e4860edc71820bf786302cf4caabd256 /hw/net/virtio-net.c
parent3f0602927b120a480b35dcf58cf6f95435b3ae91 (diff)
downloadfocaccia-qemu-043b936ef6fe53396b3c6b8f5562ea3e238a071d.tar.gz
focaccia-qemu-043b936ef6fe53396b3c6b8f5562ea3e238a071d.zip
target/m68k: fix V flag for CC_OP_SUBx
V flag for subtraction is:

   v = (res ^ src1) & (src1 ^ src2)

(see COMPUTE_CCR() in target/m68k/helper.c)

But gen_flush_flags() uses:

   v = (res ^ src2) & (src1 ^ src2)

The problem has been found with the following program:

        .global _start
_start:
        move.l  #-2147483648,%d0
        subq.l  #1,%d0
        jvc     1f
        move.l #1,%d1
        move.l #1,%d0
        trap #0
1:
        move.l #0,%d1
        move.l #1,%d0
        trap #0

It works fine (exit(1)) on real hardware, and with "-singlestep".

"-singlestep" uses gen_helper_flush_flags(), whereas
without "-singlestep", V flag is computed directly in
gen_flush_flags().

This patch updates gen_flush_flags() to have the same result
as with gen_helper_flush_flags().

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Message-Id: <20170614203905.19657-1-laurent@vivier.eu>
Diffstat (limited to 'hw/net/virtio-net.c')
0 files changed, 0 insertions, 0 deletions