On 17.10.20 04:29, Richard Henderson wrote: > Now that SUB LOGICAL outputs carry, we can use that as input directly. > It also means we can re-use CC_OP_ZC and produce an output carry > directly from SUB LOGICAL WITH BORROW. > > Signed-off-by: Richard Henderson <[email protected]> > --- > target/s390x/internal.h | 2 -- > target/s390x/cc_helper.c | 32 ----------------- > target/s390x/helper.c | 2 -- > target/s390x/translate.c | 74 ++++++++++++++++++++------------------ > target/s390x/insn-data.def | 8 ++--- > 5 files changed, 44 insertions(+), 74 deletions(-) > > diff --git a/target/s390x/internal.h b/target/s390x/internal.h > index 4077047494..11515bb617 100644 > --- a/target/s390x/internal.h > +++ b/target/s390x/internal.h > @@ -172,14 +172,12 @@ enum cc_op { > > CC_OP_ADD_64, /* overflow on add (64bit) */ > CC_OP_SUB_64, /* overflow on subtraction (64bit) */ > - CC_OP_SUBB_64, /* overflow on unsigned sub-borrow (64bit) */ > CC_OP_ABS_64, /* sign eval on abs (64bit) */ > CC_OP_NABS_64, /* sign eval on nabs (64bit) */ > CC_OP_MULS_64, /* overflow on signed multiply (64bit) */ > > CC_OP_ADD_32, /* overflow on add (32bit) */ > CC_OP_SUB_32, /* overflow on subtraction (32bit) */ > - CC_OP_SUBB_32, /* overflow on unsigned sub-borrow (32bit) */ > CC_OP_ABS_32, /* sign eval on abs (64bit) */ > CC_OP_NABS_32, /* sign eval on nabs (64bit) */ > CC_OP_MULS_32, /* overflow on signed multiply (32bit) */ > diff --git a/target/s390x/cc_helper.c b/target/s390x/cc_helper.c > index c7728d1225..e7039d0d18 100644 > --- a/target/s390x/cc_helper.c > +++ b/target/s390x/cc_helper.c > @@ -164,19 +164,6 @@ static uint32_t cc_calc_sub_64(int64_t a1, int64_t a2, > int64_t ar) > } > } > > -static uint32_t cc_calc_subb_64(uint64_t a1, uint64_t a2, uint64_t ar) > -{ > - int borrow_out; > - > - if (ar != a1 - a2) { /* difference means borrow-in */ > - borrow_out = (a2 >= a1); > - } else { > - borrow_out = (a2 > a1); > - } > - > - return (ar != 0) + 2 * !borrow_out; > -} > - > static uint32_t cc_calc_abs_64(int64_t dst) > { > if ((uint64_t)dst == 0x8000000000000000ULL) { > @@ -237,19 +224,6 @@ static uint32_t cc_calc_sub_32(int32_t a1, int32_t a2, > int32_t ar) > } > } > > -static uint32_t cc_calc_subb_32(uint32_t a1, uint32_t a2, uint32_t ar) > -{ > - int borrow_out; > - > - if (ar != a1 - a2) { /* difference means borrow-in */ > - borrow_out = (a2 >= a1); > - } else { > - borrow_out = (a2 > a1); > - } > - > - return (ar != 0) + 2 * !borrow_out; > -} > - > static uint32_t cc_calc_abs_32(int32_t dst) > { > if ((uint32_t)dst == 0x80000000UL) { > @@ -450,9 +424,6 @@ static uint32_t do_calc_cc(CPUS390XState *env, uint32_t > cc_op, > case CC_OP_SUB_64: > r = cc_calc_sub_64(src, dst, vr); > break; > - case CC_OP_SUBB_64: > - r = cc_calc_subb_64(src, dst, vr); > - break; > case CC_OP_ABS_64: > r = cc_calc_abs_64(dst); > break; > @@ -472,9 +443,6 @@ static uint32_t do_calc_cc(CPUS390XState *env, uint32_t > cc_op, > case CC_OP_SUB_32: > r = cc_calc_sub_32(src, dst, vr); > break; > - case CC_OP_SUBB_32: > - r = cc_calc_subb_32(src, dst, vr); > - break; > case CC_OP_ABS_32: > r = cc_calc_abs_32(dst); > break; > diff --git a/target/s390x/helper.c b/target/s390x/helper.c > index fa3aa500e5..7678994feb 100644 > --- a/target/s390x/helper.c > +++ b/target/s390x/helper.c > @@ -405,12 +405,10 @@ const char *cc_name(enum cc_op cc_op) > [CC_OP_LTGT0_64] = "CC_OP_LTGT0_64", > [CC_OP_ADD_64] = "CC_OP_ADD_64", > [CC_OP_SUB_64] = "CC_OP_SUB_64", > - [CC_OP_SUBB_64] = "CC_OP_SUBB_64", > [CC_OP_ABS_64] = "CC_OP_ABS_64", > [CC_OP_NABS_64] = "CC_OP_NABS_64", > [CC_OP_ADD_32] = "CC_OP_ADD_32", > [CC_OP_SUB_32] = "CC_OP_SUB_32", > - [CC_OP_SUBB_32] = "CC_OP_SUBB_32", > [CC_OP_ABS_32] = "CC_OP_ABS_32", > [CC_OP_NABS_32] = "CC_OP_NABS_32", > [CC_OP_COMP_32] = "CC_OP_COMP_32", > diff --git a/target/s390x/translate.c b/target/s390x/translate.c > index 48494a86cc..0d8235a5fb 100644 > --- a/target/s390x/translate.c > +++ b/target/s390x/translate.c > @@ -601,10 +601,8 @@ static void gen_op_calc_cc(DisasContext *s) > /* FALLTHRU */ > case CC_OP_ADD_64: > case CC_OP_SUB_64: > - case CC_OP_SUBB_64: > case CC_OP_ADD_32: > case CC_OP_SUB_32: > - case CC_OP_SUBB_32: > local_cc_op = tcg_const_i32(s->cc_op); > break; > case CC_OP_CONST0: > @@ -663,10 +661,8 @@ static void gen_op_calc_cc(DisasContext *s) > break; > case CC_OP_ADD_64: > case CC_OP_SUB_64: > - case CC_OP_SUBB_64: > case CC_OP_ADD_32: > case CC_OP_SUB_32: > - case CC_OP_SUBB_32: > /* 3 arguments */ > gen_helper_calc_cc(cc_op, cpu_env, local_cc_op, cc_src, cc_dst, > cc_vr); > break; > @@ -4744,29 +4740,49 @@ static DisasJumpType op_subu64(DisasContext *s, > DisasOps *o) > return DISAS_NEXT; > } > > -static DisasJumpType op_subb(DisasContext *s, DisasOps *o) > +/* Compute borrow (0, -1) into cc_src. */ > +static void compute_borrow(DisasContext *s) > { > - DisasCompare cmp; > - TCGv_i64 borrow; > - > - tcg_gen_sub_i64(o->out, o->in1, o->in2); > - > - /* The !borrow flag is the msb of CC. Since we want the inverse of > - that, we ask for a comparison of CC=0 | CC=1 -> mask of 8 | 4. */ > - disas_jcc(s, &cmp, 8 | 4); > - borrow = tcg_temp_new_i64(); > - if (cmp.is_64) { > - tcg_gen_setcond_i64(cmp.cond, borrow, cmp.u.s64.a, cmp.u.s64.b); > - } else { > - TCGv_i32 t = tcg_temp_new_i32(); > - tcg_gen_setcond_i32(cmp.cond, t, cmp.u.s32.a, cmp.u.s32.b); > - tcg_gen_extu_i32_i64(borrow, t); > - tcg_temp_free_i32(t); > + switch (s->cc_op) { > + case CC_OP_SUBU: > + break; > + default: > + gen_op_calc_cc(s); > + /* fall through */ > + case CC_OP_STATIC: > + /* The carry flag is the msb of CC; compute into cc_src. */ > + tcg_gen_extu_i32_i64(cc_src, cc_op); > + tcg_gen_shri_i64(cc_src, cc_src, 1); > + /* fall through */ > + case CC_OP_ADDU:
Can you give me a hint how we're converting the carry into a borrow? Can we apply something similar to compute_carry()? > + tcg_gen_subi_i64(cc_src, cc_src, 1); > + break; -- Thanks, David / dhildenb
