Re: [PATCH v2] target/i386: Use assert() to sanity-check b1 in SSE decode

2021-12-09 Thread Peter Maydell
Gave up pinging for i386 maintainers; will take this via target-arm.next.

thanks
-- PMM


On Mon, 15 Nov 2021 at 14:38, Peter Maydell  wrote:
>
> Ping^4. Who is collecting target/i386 patches these days ?
>
> -- PMM
>
> On Mon, 1 Nov 2021 at 16:18, Peter Maydell  wrote:
> >
> > Ping^3, now 2 months after patch posted and reviewed...
> >
> > -- PMM
> >
> > On Mon, 27 Sept 2021 at 11:03, Peter Maydell  
> > wrote:
> > >
> > > Ping^2 !
> > >
> > > thanks
> > > -- PMM
> > >
> > > On Mon, 13 Sept 2021 at 13:34, Peter Maydell  
> > > wrote:
> > > >
> > > > Ping? (this has been reviewed)
> > > >
> > > > thanks
> > > > -- PMM
> > > >
> > > > On Wed, 1 Sept 2021 at 15:10, Peter Maydell  
> > > > wrote:
> > > > >
> > > > > In the SSE decode function gen_sse(), we combine a byte
> > > > > 'b' and a value 'b1' which can be [0..3], and switch on them:
> > > > >b |= (b1 << 8);
> > > > >switch (b) {
> > > > >...
> > > > >default:
> > > > >unknown_op:
> > > > >gen_unknown_opcode(env, s);
> > > > >return;
> > > > >}
> > > > >
> > > > > In three cases inside this switch, we were then also checking for
> > > > >  "if (b1 >= 2) { goto unknown_op; }".
> > > > > However, this can never happen, because the 'case' values in each 
> > > > > place
> > > > > are 0x0nn or 0x1nn and the switch will have directed the b1 == (2, 3)
> > > > > cases to the default already.
> > > > >
> > > > > This check was added in commit c045af25a52e9 in 2010; the added code
> > > > > was unnecessary then as well, and was apparently intended only to
> > > > > ensure that we never accidentally ended up indexing off the end
> > > > > of an sse_op_table with only 2 entries as a result of future bugs
> > > > > in the decode logic.
> > > > >
> > > > > Change the checks to assert() instead, and make sure they're always
> > > > > immediately before the array access they are protecting.
> > > > >
> > > > > Fixes: Coverity CID 1460207
> > > > > Signed-off-by: Peter Maydell 
> > > > > ---
> > > > > v1->v2: use assert() rather than just deleting the if()s
> > > > >
> > > > >  target/i386/tcg/translate.c | 12 +++-
> > > > >  1 file changed, 3 insertions(+), 9 deletions(-)
> > > > >
> > > > > diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
> > > > > index aacb605eee4..a4fee5e445d 100644
> > > > > --- a/target/i386/tcg/translate.c
> > > > > +++ b/target/i386/tcg/translate.c
> > > > > @@ -3521,9 +3521,6 @@ static void gen_sse(CPUX86State *env, 
> > > > > DisasContext *s, int b,
> > > > >  case 0x171: /* shift xmm, im */
> > > > >  case 0x172:
> > > > >  case 0x173:
> > > > > -if (b1 >= 2) {
> > > > > -goto unknown_op;
> > > > > -}
> > > > >  val = x86_ldub_code(env, s);
> > > > >  if (is_xmm) {
> > > > >  tcg_gen_movi_tl(s->T0, val);
> > > > > @@ -3542,6 +3539,7 @@ static void gen_sse(CPUX86State *env, 
> > > > > DisasContext *s, int b,
> > > > >  offsetof(CPUX86State, 
> > > > > mmx_t0.MMX_L(1)));
> > > > >  op1_offset = offsetof(CPUX86State,mmx_t0);
> > > > >  }
> > > > > +assert(b1 < 2);
> > > > >  sse_fn_epp = sse_op_table2[((b - 1) & 3) * 8 +
> > > > > (((modrm >> 3)) & 7)][b1];
> > > > >  if (!sse_fn_epp) {
> > > > > @@ -3772,10 +3770,8 @@ static void gen_sse(CPUX86State *env, 
> > > > > DisasContext *s, int b,
> > > > >  rm = modrm & 7;
> > > > >  reg = ((modrm >> 3) & 7) | REX_R(s);
> > > > >  mod = (modrm >> 6) & 3;
> > > > > -if (b1 >= 2) {
> > > > > -goto unknown_op;
> > > > > -}
> > > > >
> > > > > +assert(b1 < 2);
> > > > >  sse_fn_epp = sse_op_table6[b].op[b1];
> > > > >  if (!sse_fn_epp) {
> > > > >  goto unknown_op;
> > > > > @@ -4202,10 +4198,8 @@ static void gen_sse(CPUX86State *env, 
> > > > > DisasContext *s, int b,
> > > > >  rm = modrm & 7;
> > > > >  reg = ((modrm >> 3) & 7) | REX_R(s);
> > > > >  mod = (modrm >> 6) & 3;
> > > > > -if (b1 >= 2) {
> > > > > -goto unknown_op;
> > > > > -}
> > > > >
> > > > > +assert(b1 < 2);
> > > > >  sse_fn_eppi = sse_op_table7[b].op[b1];
> > > > >  if (!sse_fn_eppi) {
> > > > >  goto unknown_op;
> > > > > --
> > > > > 2.20.1



Re: [PATCH v2] target/i386: Use assert() to sanity-check b1 in SSE decode

2021-11-15 Thread Peter Maydell
Ping^4. Who is collecting target/i386 patches these days ?

-- PMM

On Mon, 1 Nov 2021 at 16:18, Peter Maydell  wrote:
>
> Ping^3, now 2 months after patch posted and reviewed...
>
> -- PMM
>
> On Mon, 27 Sept 2021 at 11:03, Peter Maydell  wrote:
> >
> > Ping^2 !
> >
> > thanks
> > -- PMM
> >
> > On Mon, 13 Sept 2021 at 13:34, Peter Maydell  
> > wrote:
> > >
> > > Ping? (this has been reviewed)
> > >
> > > thanks
> > > -- PMM
> > >
> > > On Wed, 1 Sept 2021 at 15:10, Peter Maydell  
> > > wrote:
> > > >
> > > > In the SSE decode function gen_sse(), we combine a byte
> > > > 'b' and a value 'b1' which can be [0..3], and switch on them:
> > > >b |= (b1 << 8);
> > > >switch (b) {
> > > >...
> > > >default:
> > > >unknown_op:
> > > >gen_unknown_opcode(env, s);
> > > >return;
> > > >}
> > > >
> > > > In three cases inside this switch, we were then also checking for
> > > >  "if (b1 >= 2) { goto unknown_op; }".
> > > > However, this can never happen, because the 'case' values in each place
> > > > are 0x0nn or 0x1nn and the switch will have directed the b1 == (2, 3)
> > > > cases to the default already.
> > > >
> > > > This check was added in commit c045af25a52e9 in 2010; the added code
> > > > was unnecessary then as well, and was apparently intended only to
> > > > ensure that we never accidentally ended up indexing off the end
> > > > of an sse_op_table with only 2 entries as a result of future bugs
> > > > in the decode logic.
> > > >
> > > > Change the checks to assert() instead, and make sure they're always
> > > > immediately before the array access they are protecting.
> > > >
> > > > Fixes: Coverity CID 1460207
> > > > Signed-off-by: Peter Maydell 
> > > > ---
> > > > v1->v2: use assert() rather than just deleting the if()s
> > > >
> > > >  target/i386/tcg/translate.c | 12 +++-
> > > >  1 file changed, 3 insertions(+), 9 deletions(-)
> > > >
> > > > diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
> > > > index aacb605eee4..a4fee5e445d 100644
> > > > --- a/target/i386/tcg/translate.c
> > > > +++ b/target/i386/tcg/translate.c
> > > > @@ -3521,9 +3521,6 @@ static void gen_sse(CPUX86State *env, 
> > > > DisasContext *s, int b,
> > > >  case 0x171: /* shift xmm, im */
> > > >  case 0x172:
> > > >  case 0x173:
> > > > -if (b1 >= 2) {
> > > > -goto unknown_op;
> > > > -}
> > > >  val = x86_ldub_code(env, s);
> > > >  if (is_xmm) {
> > > >  tcg_gen_movi_tl(s->T0, val);
> > > > @@ -3542,6 +3539,7 @@ static void gen_sse(CPUX86State *env, 
> > > > DisasContext *s, int b,
> > > >  offsetof(CPUX86State, 
> > > > mmx_t0.MMX_L(1)));
> > > >  op1_offset = offsetof(CPUX86State,mmx_t0);
> > > >  }
> > > > +assert(b1 < 2);
> > > >  sse_fn_epp = sse_op_table2[((b - 1) & 3) * 8 +
> > > > (((modrm >> 3)) & 7)][b1];
> > > >  if (!sse_fn_epp) {
> > > > @@ -3772,10 +3770,8 @@ static void gen_sse(CPUX86State *env, 
> > > > DisasContext *s, int b,
> > > >  rm = modrm & 7;
> > > >  reg = ((modrm >> 3) & 7) | REX_R(s);
> > > >  mod = (modrm >> 6) & 3;
> > > > -if (b1 >= 2) {
> > > > -goto unknown_op;
> > > > -}
> > > >
> > > > +assert(b1 < 2);
> > > >  sse_fn_epp = sse_op_table6[b].op[b1];
> > > >  if (!sse_fn_epp) {
> > > >  goto unknown_op;
> > > > @@ -4202,10 +4198,8 @@ static void gen_sse(CPUX86State *env, 
> > > > DisasContext *s, int b,
> > > >  rm = modrm & 7;
> > > >  reg = ((modrm >> 3) & 7) | REX_R(s);
> > > >  mod = (modrm >> 6) & 3;
> > > > -if (b1 >= 2) {
> > > > -goto unknown_op;
> > > > -}
> > > >
> > > > +assert(b1 < 2);
> > > >  sse_fn_eppi = sse_op_table7[b].op[b1];
> > > >  if (!sse_fn_eppi) {
> > > >  goto unknown_op;
> > > > --
> > > > 2.20.1



Re: [PATCH v2] target/i386: Use assert() to sanity-check b1 in SSE decode

2021-11-01 Thread Peter Maydell
Ping^3, now 2 months after patch posted and reviewed...

-- PMM

On Mon, 27 Sept 2021 at 11:03, Peter Maydell  wrote:
>
> Ping^2 !
>
> thanks
> -- PMM
>
> On Mon, 13 Sept 2021 at 13:34, Peter Maydell  wrote:
> >
> > Ping? (this has been reviewed)
> >
> > thanks
> > -- PMM
> >
> > On Wed, 1 Sept 2021 at 15:10, Peter Maydell  
> > wrote:
> > >
> > > In the SSE decode function gen_sse(), we combine a byte
> > > 'b' and a value 'b1' which can be [0..3], and switch on them:
> > >b |= (b1 << 8);
> > >switch (b) {
> > >...
> > >default:
> > >unknown_op:
> > >gen_unknown_opcode(env, s);
> > >return;
> > >}
> > >
> > > In three cases inside this switch, we were then also checking for
> > >  "if (b1 >= 2) { goto unknown_op; }".
> > > However, this can never happen, because the 'case' values in each place
> > > are 0x0nn or 0x1nn and the switch will have directed the b1 == (2, 3)
> > > cases to the default already.
> > >
> > > This check was added in commit c045af25a52e9 in 2010; the added code
> > > was unnecessary then as well, and was apparently intended only to
> > > ensure that we never accidentally ended up indexing off the end
> > > of an sse_op_table with only 2 entries as a result of future bugs
> > > in the decode logic.
> > >
> > > Change the checks to assert() instead, and make sure they're always
> > > immediately before the array access they are protecting.
> > >
> > > Fixes: Coverity CID 1460207
> > > Signed-off-by: Peter Maydell 
> > > ---
> > > v1->v2: use assert() rather than just deleting the if()s
> > >
> > >  target/i386/tcg/translate.c | 12 +++-
> > >  1 file changed, 3 insertions(+), 9 deletions(-)
> > >
> > > diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
> > > index aacb605eee4..a4fee5e445d 100644
> > > --- a/target/i386/tcg/translate.c
> > > +++ b/target/i386/tcg/translate.c
> > > @@ -3521,9 +3521,6 @@ static void gen_sse(CPUX86State *env, DisasContext 
> > > *s, int b,
> > >  case 0x171: /* shift xmm, im */
> > >  case 0x172:
> > >  case 0x173:
> > > -if (b1 >= 2) {
> > > -goto unknown_op;
> > > -}
> > >  val = x86_ldub_code(env, s);
> > >  if (is_xmm) {
> > >  tcg_gen_movi_tl(s->T0, val);
> > > @@ -3542,6 +3539,7 @@ static void gen_sse(CPUX86State *env, DisasContext 
> > > *s, int b,
> > >  offsetof(CPUX86State, mmx_t0.MMX_L(1)));
> > >  op1_offset = offsetof(CPUX86State,mmx_t0);
> > >  }
> > > +assert(b1 < 2);
> > >  sse_fn_epp = sse_op_table2[((b - 1) & 3) * 8 +
> > > (((modrm >> 3)) & 7)][b1];
> > >  if (!sse_fn_epp) {
> > > @@ -3772,10 +3770,8 @@ static void gen_sse(CPUX86State *env, DisasContext 
> > > *s, int b,
> > >  rm = modrm & 7;
> > >  reg = ((modrm >> 3) & 7) | REX_R(s);
> > >  mod = (modrm >> 6) & 3;
> > > -if (b1 >= 2) {
> > > -goto unknown_op;
> > > -}
> > >
> > > +assert(b1 < 2);
> > >  sse_fn_epp = sse_op_table6[b].op[b1];
> > >  if (!sse_fn_epp) {
> > >  goto unknown_op;
> > > @@ -4202,10 +4198,8 @@ static void gen_sse(CPUX86State *env, DisasContext 
> > > *s, int b,
> > >  rm = modrm & 7;
> > >  reg = ((modrm >> 3) & 7) | REX_R(s);
> > >  mod = (modrm >> 6) & 3;
> > > -if (b1 >= 2) {
> > > -goto unknown_op;
> > > -}
> > >
> > > +assert(b1 < 2);
> > >  sse_fn_eppi = sse_op_table7[b].op[b1];
> > >  if (!sse_fn_eppi) {
> > >  goto unknown_op;
> > > --
> > > 2.20.1



Re: [PATCH v2] target/i386: Use assert() to sanity-check b1 in SSE decode

2021-09-27 Thread Peter Maydell
Ping^2 !

thanks
-- PMM

On Mon, 13 Sept 2021 at 13:34, Peter Maydell  wrote:
>
> Ping? (this has been reviewed)
>
> thanks
> -- PMM
>
> On Wed, 1 Sept 2021 at 15:10, Peter Maydell  wrote:
> >
> > In the SSE decode function gen_sse(), we combine a byte
> > 'b' and a value 'b1' which can be [0..3], and switch on them:
> >b |= (b1 << 8);
> >switch (b) {
> >...
> >default:
> >unknown_op:
> >gen_unknown_opcode(env, s);
> >return;
> >}
> >
> > In three cases inside this switch, we were then also checking for
> >  "if (b1 >= 2) { goto unknown_op; }".
> > However, this can never happen, because the 'case' values in each place
> > are 0x0nn or 0x1nn and the switch will have directed the b1 == (2, 3)
> > cases to the default already.
> >
> > This check was added in commit c045af25a52e9 in 2010; the added code
> > was unnecessary then as well, and was apparently intended only to
> > ensure that we never accidentally ended up indexing off the end
> > of an sse_op_table with only 2 entries as a result of future bugs
> > in the decode logic.
> >
> > Change the checks to assert() instead, and make sure they're always
> > immediately before the array access they are protecting.
> >
> > Fixes: Coverity CID 1460207
> > Signed-off-by: Peter Maydell 
> > ---
> > v1->v2: use assert() rather than just deleting the if()s
> >
> >  target/i386/tcg/translate.c | 12 +++-
> >  1 file changed, 3 insertions(+), 9 deletions(-)
> >
> > diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
> > index aacb605eee4..a4fee5e445d 100644
> > --- a/target/i386/tcg/translate.c
> > +++ b/target/i386/tcg/translate.c
> > @@ -3521,9 +3521,6 @@ static void gen_sse(CPUX86State *env, DisasContext 
> > *s, int b,
> >  case 0x171: /* shift xmm, im */
> >  case 0x172:
> >  case 0x173:
> > -if (b1 >= 2) {
> > -goto unknown_op;
> > -}
> >  val = x86_ldub_code(env, s);
> >  if (is_xmm) {
> >  tcg_gen_movi_tl(s->T0, val);
> > @@ -3542,6 +3539,7 @@ static void gen_sse(CPUX86State *env, DisasContext 
> > *s, int b,
> >  offsetof(CPUX86State, mmx_t0.MMX_L(1)));
> >  op1_offset = offsetof(CPUX86State,mmx_t0);
> >  }
> > +assert(b1 < 2);
> >  sse_fn_epp = sse_op_table2[((b - 1) & 3) * 8 +
> > (((modrm >> 3)) & 7)][b1];
> >  if (!sse_fn_epp) {
> > @@ -3772,10 +3770,8 @@ static void gen_sse(CPUX86State *env, DisasContext 
> > *s, int b,
> >  rm = modrm & 7;
> >  reg = ((modrm >> 3) & 7) | REX_R(s);
> >  mod = (modrm >> 6) & 3;
> > -if (b1 >= 2) {
> > -goto unknown_op;
> > -}
> >
> > +assert(b1 < 2);
> >  sse_fn_epp = sse_op_table6[b].op[b1];
> >  if (!sse_fn_epp) {
> >  goto unknown_op;
> > @@ -4202,10 +4198,8 @@ static void gen_sse(CPUX86State *env, DisasContext 
> > *s, int b,
> >  rm = modrm & 7;
> >  reg = ((modrm >> 3) & 7) | REX_R(s);
> >  mod = (modrm >> 6) & 3;
> > -if (b1 >= 2) {
> > -goto unknown_op;
> > -}
> >
> > +assert(b1 < 2);
> >  sse_fn_eppi = sse_op_table7[b].op[b1];
> >  if (!sse_fn_eppi) {
> >  goto unknown_op;
> > --
> > 2.20.1



Re: [PATCH v2] target/i386: Use assert() to sanity-check b1 in SSE decode

2021-09-13 Thread Peter Maydell
Ping? (this has been reviewed)

thanks
-- PMM

On Wed, 1 Sept 2021 at 15:10, Peter Maydell  wrote:
>
> In the SSE decode function gen_sse(), we combine a byte
> 'b' and a value 'b1' which can be [0..3], and switch on them:
>b |= (b1 << 8);
>switch (b) {
>...
>default:
>unknown_op:
>gen_unknown_opcode(env, s);
>return;
>}
>
> In three cases inside this switch, we were then also checking for
>  "if (b1 >= 2) { goto unknown_op; }".
> However, this can never happen, because the 'case' values in each place
> are 0x0nn or 0x1nn and the switch will have directed the b1 == (2, 3)
> cases to the default already.
>
> This check was added in commit c045af25a52e9 in 2010; the added code
> was unnecessary then as well, and was apparently intended only to
> ensure that we never accidentally ended up indexing off the end
> of an sse_op_table with only 2 entries as a result of future bugs
> in the decode logic.
>
> Change the checks to assert() instead, and make sure they're always
> immediately before the array access they are protecting.
>
> Fixes: Coverity CID 1460207
> Signed-off-by: Peter Maydell 
> ---
> v1->v2: use assert() rather than just deleting the if()s
>
>  target/i386/tcg/translate.c | 12 +++-
>  1 file changed, 3 insertions(+), 9 deletions(-)
>
> diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
> index aacb605eee4..a4fee5e445d 100644
> --- a/target/i386/tcg/translate.c
> +++ b/target/i386/tcg/translate.c
> @@ -3521,9 +3521,6 @@ static void gen_sse(CPUX86State *env, DisasContext *s, 
> int b,
>  case 0x171: /* shift xmm, im */
>  case 0x172:
>  case 0x173:
> -if (b1 >= 2) {
> -goto unknown_op;
> -}
>  val = x86_ldub_code(env, s);
>  if (is_xmm) {
>  tcg_gen_movi_tl(s->T0, val);
> @@ -3542,6 +3539,7 @@ static void gen_sse(CPUX86State *env, DisasContext *s, 
> int b,
>  offsetof(CPUX86State, mmx_t0.MMX_L(1)));
>  op1_offset = offsetof(CPUX86State,mmx_t0);
>  }
> +assert(b1 < 2);
>  sse_fn_epp = sse_op_table2[((b - 1) & 3) * 8 +
> (((modrm >> 3)) & 7)][b1];
>  if (!sse_fn_epp) {
> @@ -3772,10 +3770,8 @@ static void gen_sse(CPUX86State *env, DisasContext *s, 
> int b,
>  rm = modrm & 7;
>  reg = ((modrm >> 3) & 7) | REX_R(s);
>  mod = (modrm >> 6) & 3;
> -if (b1 >= 2) {
> -goto unknown_op;
> -}
>
> +assert(b1 < 2);
>  sse_fn_epp = sse_op_table6[b].op[b1];
>  if (!sse_fn_epp) {
>  goto unknown_op;
> @@ -4202,10 +4198,8 @@ static void gen_sse(CPUX86State *env, DisasContext *s, 
> int b,
>  rm = modrm & 7;
>  reg = ((modrm >> 3) & 7) | REX_R(s);
>  mod = (modrm >> 6) & 3;
> -if (b1 >= 2) {
> -goto unknown_op;
> -}
>
> +assert(b1 < 2);
>  sse_fn_eppi = sse_op_table7[b].op[b1];
>  if (!sse_fn_eppi) {
>  goto unknown_op;
> --
> 2.20.1



Re: [PATCH v2] target/i386: Use assert() to sanity-check b1 in SSE decode

2021-09-03 Thread Richard Henderson

On 9/1/21 4:10 PM, Peter Maydell wrote:

In the SSE decode function gen_sse(), we combine a byte
'b' and a value 'b1' which can be [0..3], and switch on them:
b |= (b1 << 8);
switch (b) {
...
default:
unknown_op:
gen_unknown_opcode(env, s);
return;
}

In three cases inside this switch, we were then also checking for
  "if (b1 >= 2) { goto unknown_op; }".
However, this can never happen, because the 'case' values in each place
are 0x0nn or 0x1nn and the switch will have directed the b1 == (2, 3)
cases to the default already.

This check was added in commit c045af25a52e9 in 2010; the added code
was unnecessary then as well, and was apparently intended only to
ensure that we never accidentally ended up indexing off the end
of an sse_op_table with only 2 entries as a result of future bugs
in the decode logic.

Change the checks to assert() instead, and make sure they're always
immediately before the array access they are protecting.

Fixes: Coverity CID 1460207
Signed-off-by: Peter Maydell
---
v1->v2: use assert() rather than just deleting the if()s


Reviewed-by: Richard Henderson 

r~



[PATCH v2] target/i386: Use assert() to sanity-check b1 in SSE decode

2021-09-01 Thread Peter Maydell
In the SSE decode function gen_sse(), we combine a byte
'b' and a value 'b1' which can be [0..3], and switch on them:
   b |= (b1 << 8);
   switch (b) {
   ...
   default:
   unknown_op:
   gen_unknown_opcode(env, s);
   return;
   }

In three cases inside this switch, we were then also checking for
 "if (b1 >= 2) { goto unknown_op; }".
However, this can never happen, because the 'case' values in each place
are 0x0nn or 0x1nn and the switch will have directed the b1 == (2, 3)
cases to the default already.

This check was added in commit c045af25a52e9 in 2010; the added code
was unnecessary then as well, and was apparently intended only to
ensure that we never accidentally ended up indexing off the end
of an sse_op_table with only 2 entries as a result of future bugs
in the decode logic.

Change the checks to assert() instead, and make sure they're always
immediately before the array access they are protecting.

Fixes: Coverity CID 1460207
Signed-off-by: Peter Maydell 
---
v1->v2: use assert() rather than just deleting the if()s

 target/i386/tcg/translate.c | 12 +++-
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
index aacb605eee4..a4fee5e445d 100644
--- a/target/i386/tcg/translate.c
+++ b/target/i386/tcg/translate.c
@@ -3521,9 +3521,6 @@ static void gen_sse(CPUX86State *env, DisasContext *s, 
int b,
 case 0x171: /* shift xmm, im */
 case 0x172:
 case 0x173:
-if (b1 >= 2) {
-goto unknown_op;
-}
 val = x86_ldub_code(env, s);
 if (is_xmm) {
 tcg_gen_movi_tl(s->T0, val);
@@ -3542,6 +3539,7 @@ static void gen_sse(CPUX86State *env, DisasContext *s, 
int b,
 offsetof(CPUX86State, mmx_t0.MMX_L(1)));
 op1_offset = offsetof(CPUX86State,mmx_t0);
 }
+assert(b1 < 2);
 sse_fn_epp = sse_op_table2[((b - 1) & 3) * 8 +
(((modrm >> 3)) & 7)][b1];
 if (!sse_fn_epp) {
@@ -3772,10 +3770,8 @@ static void gen_sse(CPUX86State *env, DisasContext *s, 
int b,
 rm = modrm & 7;
 reg = ((modrm >> 3) & 7) | REX_R(s);
 mod = (modrm >> 6) & 3;
-if (b1 >= 2) {
-goto unknown_op;
-}
 
+assert(b1 < 2);
 sse_fn_epp = sse_op_table6[b].op[b1];
 if (!sse_fn_epp) {
 goto unknown_op;
@@ -4202,10 +4198,8 @@ static void gen_sse(CPUX86State *env, DisasContext *s, 
int b,
 rm = modrm & 7;
 reg = ((modrm >> 3) & 7) | REX_R(s);
 mod = (modrm >> 6) & 3;
-if (b1 >= 2) {
-goto unknown_op;
-}
 
+assert(b1 < 2);
 sse_fn_eppi = sse_op_table7[b].op[b1];
 if (!sse_fn_eppi) {
 goto unknown_op;
-- 
2.20.1