Re: [Qemu-devel] [PATCH 7/7] target/s390x: implement CVB, CVBY and CVBG

[David Hildenbrand]

On 21.08.2018 04:51, Pavel Zbitskiy wrote:
> Convert to Binary - counterparts of the already implemented Convert
> to Decimal (CVD*) instructions.
> Example from the Principles of Operation: 25594C becomes 63FA.
> 
> Signed-off-by: Pavel Zbitskiy <address@hidden>
> ---
>  target/s390x/helper.h           |  1 +
>  target/s390x/insn-data.def      |  4 +++
>  target/s390x/int_helper.c       | 50 +++++++++++++++++++++++++++++++++
>  target/s390x/translate.c        | 10 +++++++
>  tests/tcg/s390x/Makefile.target |  1 +
>  tests/tcg/s390x/cvb.c           | 18 ++++++++++++
>  6 files changed, 84 insertions(+)
>  create mode 100644 tests/tcg/s390x/cvb.c
> 
> diff --git a/target/s390x/helper.h b/target/s390x/helper.h
> index 97c60ca7bc..46baaee0ab 100644
> --- a/target/s390x/helper.h
> +++ b/target/s390x/helper.h
> @@ -88,6 +88,7 @@ DEF_HELPER_FLAGS_4(tcxb, TCG_CALL_NO_RWG_SE, i32, env, i64, 
> i64, i64)
>  DEF_HELPER_FLAGS_2(sqeb, TCG_CALL_NO_WG, i64, env, i64)
>  DEF_HELPER_FLAGS_2(sqdb, TCG_CALL_NO_WG, i64, env, i64)
>  DEF_HELPER_FLAGS_3(sqxb, TCG_CALL_NO_WG, i64, env, i64, i64)
> +DEF_HELPER_FLAGS_3(cvb, TCG_CALL_NO_WG, i64, env, i64, i32)
>  DEF_HELPER_FLAGS_1(cvd, TCG_CALL_NO_RWG_SE, i64, s32)
>  DEF_HELPER_FLAGS_4(pack, TCG_CALL_NO_WG, void, env, i32, i64, i64)
>  DEF_HELPER_FLAGS_4(pka, TCG_CALL_NO_WG, void, env, i64, i64, i32)
> diff --git a/target/s390x/insn-data.def b/target/s390x/insn-data.def
> index 9c7b434fca..1b29a5e044 100644
> --- a/target/s390x/insn-data.def
> +++ b/target/s390x/insn-data.def
> @@ -284,6 +284,10 @@
>      D(0xec73, CLFIT,   RIE_a, GIE, r1_32u, i2_32u, 0, 0, ct, 0, 1)
>      D(0xec71, CLGIT,   RIE_a, GIE, r1_o, i2_32u, 0, 0, ct, 0, 1)
>  
> +/* CONVERT TO BINARY */
> +    C(0x4f00, CVB,     RX_a,  Z,   0, a2, new, r1_32, cvb, 0)
> +    C(0xe306, CVBY,    RXY_a, LD,  0, a2, new, r1_32, cvb, 0)
> +    C(0xe30e, CVBG,    RXY_a, Z,   0, a2, r1, 0, cvb, 0)

use in1_la2 instead, so you can use o->addr in the handler.

>  /* CONVERT TO DECIMAL */
>      C(0x4e00, CVD,     RX_a,  Z,   r1_o, a2, 0, 0, cvd, 0)
>      C(0xe326, CVDY,    RXY_a, LD,  r1_o, a2, 0, 0, cvd, 0)
> diff --git a/target/s390x/int_helper.c b/target/s390x/int_helper.c
> index abf77a94e6..66c6dc8b3a 100644
> --- a/target/s390x/int_helper.c
> +++ b/target/s390x/int_helper.c
> @@ -24,6 +24,7 @@
>  #include "exec/exec-all.h"
>  #include "qemu/host-utils.h"
>  #include "exec/helper-proto.h"
> +#include "exec/cpu_ldst.h"
>  
>  /* #define DEBUG_HELPER */
>  #ifdef DEBUG_HELPER
> @@ -118,6 +119,55 @@ uint64_t HELPER(divu64)(CPUS390XState *env, uint64_t ah, 
> uint64_t al,
>      return ret;
>  }
>  
> +static void general_operand_exception(CPUS390XState *env, uintptr_t ra)
> +{
> +#ifndef CONFIG_USER_ONLY
> +    LowCore *lowcore;
> +
> +    lowcore = cpu_map_lowcore(env);
> +    lowcore->data_exc_code = 0;
> +    cpu_unmap_lowcore(lowcore);
> +#endif
> +    s390_program_interrupt(env, PGM_DATA, ILEN_AUTO, ra);
> +}
> +
> +uint64_t HELPER(cvb)(CPUS390XState *env, uint64_t src, uint32_t n)
> +{
> +    int i, j;
> +    uintptr_t ra = GETPC();

You could make this const

> +    int64_t dec, sign = 0, digit, val = 0, pow10 = 0;
> +
> +    for (i = 0; i < n; i++) {

When manually creating addresses, we should usually wrap to catch some
special cases (address space wraparound).

tmpsrc = wrap_address(env, src + (n - i - 1) * 8);

> +        dec = cpu_ldq_data_ra(env, src + (n - i - 1) * 8, ra);
> +        for (j = 0; j < 16; j++, dec >>= 4) {
> +            if (i == 0 && j == 0) {
> +                sign = dec & 0xf;
> +                if (sign < 0xa) {
> +                    general_operand_exception(env, ra);
> +                }
> +                continue;
> +            }
> +            digit = dec & 0xf;
> +            if (digit > 0x9) {
> +                general_operand_exception(env, ra);
> +            }
> +            if (i == 0 && j == 1) {
> +                if (sign == 0xb || sign == 0xd) {
> +                    val = -digit;
> +                    pow10 = -10;
> +                } else {
> +                    val = digit;
> +                    pow10 = 10;
> +                }
> +            } else {
> +                val += digit * pow10;
> +                pow10 *= 10;
> +            }
> +        }
> +    }
> +    return val;
> +}
> +
>  uint64_t HELPER(cvd)(int32_t reg)
>  {
>      /* positive 0 */
> diff --git a/target/s390x/translate.c b/target/s390x/translate.c
> index f58b36b789..b3cbfead5d 100644
> --- a/target/s390x/translate.c
> +++ b/target/s390x/translate.c
> @@ -2115,6 +2115,16 @@ static DisasJumpType op_csp(DisasContext *s, DisasOps 
> *o)
>  }
>  #endif
>  
> +static DisasJumpType op_cvb(DisasContext *s, DisasOps *o)
> +{
> +    uint64_t n = ((s->fields->op == 0xE3) && (s->fields->op2 == 0x0E)) ?
> +        /* CVBG */      2 :
> +        /* CVB, CVBY */ 1;
> +
> +    gen_helper_cvb(o->out, cpu_env, o->in2, tcg_const_i32(n));

You are missing to free the tcg_const_i32() created variable.

> +    return DISAS_NEXT;
> +}
> +



-- 

Thanks,

David / dhildenb