Message ID | 20210529130520.1039274-1-f4bug@amsat.org (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | target/mips: Fix DBALIGN DSP-R2 opcode 'byte position' field size | expand |
On 5/29/21 3:05 PM, Philippe Mathieu-Daudé wrote: > Per the "MIPS® DSP Module for MIPS64 Architecture" manual (rev 3.02), > Figure 5.12 "SPECIAL3 Encoding of APPEND/DAPPEND Instruction Sub-class" > the byte position field ('bp') is 2 bits, not 3. > > Cc: Jia Liu <proljc@gmail.com> > Fixes: 26690560240 ("target-mips: Add ASE DSP compare-pick instructions") > Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> > --- > target/mips/tcg/translate.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/target/mips/tcg/translate.c b/target/mips/tcg/translate.c > index c03a8ae1fed..e68647ce14c 100644 > --- a/target/mips/tcg/translate.c > +++ b/target/mips/tcg/translate.c > @@ -23016,8 +23016,8 @@ static void gen_mipsdsp_append(CPUMIPSState *env, DisasContext *ctx, > } > break; > case OPC_DBALIGN: > - sa &= 7; > - if (sa != 0 && sa != 2 && sa != 4) { > + sa &= 3; > + if (sa != 0 && sa != 2) { > tcg_gen_shli_tl(cpu_gpr[rt], cpu_gpr[rt], 8 * sa); > tcg_gen_shri_tl(t0, t0, 8 * (8 - sa)); > tcg_gen_or_tl(cpu_gpr[rt], cpu_gpr[rt], t0); > Looking at GCC, there is a patch adding this opcode: https://gcc.gnu.org/legacy-ml/gcc-patches/2012-02/msg00127.html which uses 2 bits: +(define_insn "mips_dbalign" + [(set (match_operand:DI 0 "register_operand" "=d") + (unspec:DI [(match_operand:DI 1 "register_operand" "0") + (match_operand:DI 2 "reg_or_0_operand" "dJ") + (match_operand:DI 3 "const_int_operand" "n")] + UNSPEC_DBALIGN))] + "ISA_HAS_DSPR2" +{ + if (INTVAL (operands[3]) & ~(unsigned HOST_WIDE_INT) 3) + operands[2] = GEN_INT (INTVAL (operands[2]) & 3); + return "dbalign\t%0,%z2,%3"; +} + [(set_attr "type" "arith") + (set_attr "mode" "DI")]) However looking at the releases/gcc-11.1.0 tag it seems GCC never supported DBALIGN...: https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/config/mips/mips-dspr2.md;h=95ba712f6a12946100cd4fe98d05732e70de8f98;hb=50bc9185c2821350f0b785d6e23a6e9dcde58466
On 5/29/21 6:05 AM, Philippe Mathieu-Daudé wrote: > Per the "MIPS® DSP Module for MIPS64 Architecture" manual (rev 3.02), > Figure 5.12 "SPECIAL3 Encoding of APPEND/DAPPEND Instruction Sub-class" > the byte position field ('bp') is 2 bits, not 3. Rev 2.34 has 3 bits, not 2. The mips32 version of balign, that uses 2 bits... Are you sure you looked at the right instruction? Because 3 bits makes most sense for this instruction with a 64-bit register size. r~ > > Cc: Jia Liu <proljc@gmail.com> > Fixes: 26690560240 ("target-mips: Add ASE DSP compare-pick instructions") > Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> > --- > target/mips/tcg/translate.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/target/mips/tcg/translate.c b/target/mips/tcg/translate.c > index c03a8ae1fed..e68647ce14c 100644 > --- a/target/mips/tcg/translate.c > +++ b/target/mips/tcg/translate.c > @@ -23016,8 +23016,8 @@ static void gen_mipsdsp_append(CPUMIPSState *env, DisasContext *ctx, > } > break; > case OPC_DBALIGN: > - sa &= 7; > - if (sa != 0 && sa != 2 && sa != 4) { > + sa &= 3; > + if (sa != 0 && sa != 2) { > tcg_gen_shli_tl(cpu_gpr[rt], cpu_gpr[rt], 8 * sa); > tcg_gen_shri_tl(t0, t0, 8 * (8 - sa)); > tcg_gen_or_tl(cpu_gpr[rt], cpu_gpr[rt], t0); >
On 5/30/21 5:33 PM, Richard Henderson wrote: > On 5/29/21 6:05 AM, Philippe Mathieu-Daudé wrote: >> Per the "MIPS® DSP Module for MIPS64 Architecture" manual (rev 3.02), >> Figure 5.12 "SPECIAL3 Encoding of APPEND/DAPPEND Instruction Sub-class" >> the byte position field ('bp') is 2 bits, not 3. > > Rev 2.34 has 3 bits, not 2. > > The mips32 version of balign, that uses 2 bits... Are you sure you > looked at the right instruction? Because 3 bits makes most sense for > this instruction with a 64-bit register size. Yes indeed it makes sense, and Rev 3.02 is incomplete... Thanks, Phil.
diff --git a/target/mips/tcg/translate.c b/target/mips/tcg/translate.c index c03a8ae1fed..e68647ce14c 100644 --- a/target/mips/tcg/translate.c +++ b/target/mips/tcg/translate.c @@ -23016,8 +23016,8 @@ static void gen_mipsdsp_append(CPUMIPSState *env, DisasContext *ctx, } break; case OPC_DBALIGN: - sa &= 7; - if (sa != 0 && sa != 2 && sa != 4) { + sa &= 3; + if (sa != 0 && sa != 2) { tcg_gen_shli_tl(cpu_gpr[rt], cpu_gpr[rt], 8 * sa); tcg_gen_shri_tl(t0, t0, 8 * (8 - sa)); tcg_gen_or_tl(cpu_gpr[rt], cpu_gpr[rt], t0);
Per the "MIPS® DSP Module for MIPS64 Architecture" manual (rev 3.02), Figure 5.12 "SPECIAL3 Encoding of APPEND/DAPPEND Instruction Sub-class" the byte position field ('bp') is 2 bits, not 3. Cc: Jia Liu <proljc@gmail.com> Fixes: 26690560240 ("target-mips: Add ASE DSP compare-pick instructions") Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> --- target/mips/tcg/translate.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)