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Re: [Qemu-devel] [PATCH v4] ppc: Add support for 'mffsl' instruction
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From: |
David Gibson |
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Subject: |
Re: [Qemu-devel] [PATCH v4] ppc: Add support for 'mffsl' instruction |
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Date: |
Sat, 17 Aug 2019 18:18:11 +1000 |
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User-agent: |
Mutt/1.12.1 (2019-06-15) |
On Fri, Aug 16, 2019 at 02:03:23PM -0500, Paul A. Clarke wrote:
65;5603;1c> From: "Paul A. Clarke" <address@hidden>
>
> ISA 3.0B added a set of Floating-Point Status and Control Register (FPSCR)
> instructions: mffsce, mffscdrn, mffscdrni, mffscrn, mffscrni, mffsl.
> This patch adds support for 'mffsl'.
>
> 'mffsl' is identical to 'mffs', except it only returns mode, status, and
> enable
> bits from the FPSCR.
>
> On CPUs without support for 'mffsl' (below ISA 3.0), the 'mffsl' instruction
> will execute identically to 'mffs'.
>
> Note: I renamed FPSCR_RN to FPSCR_RN0 so I could create an FPSCR_RN mask which
> is both bits of the FPSCR rounding mode, as defined in the ISA.
>
> I also fixed a typo in the definition of FPSCR_FR.
>
> Signed-off-by: Paul A. Clarke <address@hidden>
Applied to ppc-for-4.2, thanks.
>
> v4:
> - nit: added some braces to resolve a checkpatch complaint.
>
> v3:
> - Changed tcg_gen_and_i64 to tcg_gen_andi_i64, eliminating the need for a
> temporary, per review from Richard Henderson.
>
> v2:
> - I found that I copied too much of the 'mffs' implementation.
> The 'Rc' condition code bits are not needed for 'mffsl'. Removed.
> - I now free the (renamed) 'tmask' temporary.
> - I now bail early for older ISA to the original 'mffs' implementation.
>
> ---
> disas/ppc.c | 5 +++++
> target/ppc/cpu.h | 15 ++++++++++-----
> target/ppc/fpu_helper.c | 4 ++--
> target/ppc/translate/fp-impl.inc.c | 22 ++++++++++++++++++++++
> target/ppc/translate/fp-ops.inc.c | 4 +++-
> 5 files changed, 42 insertions(+), 8 deletions(-)
>
> diff --git a/disas/ppc.c b/disas/ppc.c
> index a545437..63e97cf 100644
> --- a/disas/ppc.c
> +++ b/disas/ppc.c
> @@ -1765,6 +1765,9 @@ extract_tbr (unsigned long insn,
> /* An X_MASK with the RA and RB fields fixed. */
> #define XRARB_MASK (X_MASK | RA_MASK | RB_MASK)
>
> +/* An X form instruction with the RA field fixed. */
> +#define XRA(op, xop, ra) (X((op), (xop)) | (((ra) << 16) & XRA_MASK))
> +
> /* An XRARB_MASK, but with the L bit clear. */
> #define XRLARB_MASK (XRARB_MASK & ~((unsigned long) 1 << 16))
>
> @@ -4998,6 +5001,8 @@ const struct powerpc_opcode powerpc_opcodes[] = {
> { "ddivq", XRC(63,546,0), X_MASK, POWER6, { FRT, FRA, FRB } },
> { "ddivq.", XRC(63,546,1), X_MASK, POWER6, { FRT, FRA, FRB } },
>
> +{ "mffsl", XRA(63,583,12), XRARB_MASK, POWER9, { FRT } },
> +
> { "mffs", XRC(63,583,0), XRARB_MASK, COM, { FRT } },
> { "mffs.", XRC(63,583,1), XRARB_MASK, COM, { FRT } },
>
> diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
> index c9beba2..74e8da4 100644
> --- a/target/ppc/cpu.h
> +++ b/target/ppc/cpu.h
> @@ -591,7 +591,7 @@ enum {
> #define FPSCR_XE 3 /* Floating-point inexact exception enable
> */
> #define FPSCR_NI 2 /* Floating-point non-IEEE mode
> */
> #define FPSCR_RN1 1
> -#define FPSCR_RN 0 /* Floating-point rounding control
> */
> +#define FPSCR_RN0 0 /* Floating-point rounding control
> */
> #define fpscr_fex (((env->fpscr) >> FPSCR_FEX) & 0x1)
> #define fpscr_vx (((env->fpscr) >> FPSCR_VX) & 0x1)
> #define fpscr_ox (((env->fpscr) >> FPSCR_OX) & 0x1)
> @@ -614,7 +614,7 @@ enum {
> #define fpscr_ze (((env->fpscr) >> FPSCR_ZE) & 0x1)
> #define fpscr_xe (((env->fpscr) >> FPSCR_XE) & 0x1)
> #define fpscr_ni (((env->fpscr) >> FPSCR_NI) & 0x1)
> -#define fpscr_rn (((env->fpscr) >> FPSCR_RN) & 0x3)
> +#define fpscr_rn (((env->fpscr) >> FPSCR_RN0) & 0x3)
> /* Invalid operation exception summary */
> #define fpscr_ix ((env->fpscr) & ((1 << FPSCR_VXSNAN) | (1 << FPSCR_VXISI)
> | \
> (1 << FPSCR_VXIDI) | (1 << FPSCR_VXZDZ)
> | \
> @@ -640,7 +640,7 @@ enum {
> #define FP_VXZDZ (1ull << FPSCR_VXZDZ)
> #define FP_VXIMZ (1ull << FPSCR_VXIMZ)
> #define FP_VXVC (1ull << FPSCR_VXVC)
> -#define FP_FR (1ull << FSPCR_FR)
> +#define FP_FR (1ull << FPSCR_FR)
> #define FP_FI (1ull << FPSCR_FI)
> #define FP_C (1ull << FPSCR_C)
> #define FP_FL (1ull << FPSCR_FL)
> @@ -648,7 +648,7 @@ enum {
> #define FP_FE (1ull << FPSCR_FE)
> #define FP_FU (1ull << FPSCR_FU)
> #define FP_FPCC (FP_FL | FP_FG | FP_FE | FP_FU)
> -#define FP_FPRF (FP_C | FP_FL | FP_FG | FP_FE | FP_FU)
> +#define FP_FPRF (FP_C | FP_FPCC)
> #define FP_VXSOFT (1ull << FPSCR_VXSOFT)
> #define FP_VXSQRT (1ull << FPSCR_VXSQRT)
> #define FP_VXCVI (1ull << FPSCR_VXCVI)
> @@ -659,7 +659,12 @@ enum {
> #define FP_XE (1ull << FPSCR_XE)
> #define FP_NI (1ull << FPSCR_NI)
> #define FP_RN1 (1ull << FPSCR_RN1)
> -#define FP_RN (1ull << FPSCR_RN)
> +#define FP_RN0 (1ull << FPSCR_RN0)
> +#define FP_RN (FP_RN1 | FP_RN0)
> +
> +#define FP_MODE FP_RN
> +#define FP_ENABLES (FP_VE | FP_OE | FP_UE | FP_ZE | FP_XE)
> +#define FP_STATUS (FP_FR | FP_FI | FP_FPRF)
>
> /* the exception bits which can be cleared by mcrfs - includes FX */
> #define FP_EX_CLEAR_BITS (FP_FX | FP_OX | FP_UX | FP_ZX | \
> diff --git a/target/ppc/fpu_helper.c b/target/ppc/fpu_helper.c
> index f437c88..5611cf0 100644
> --- a/target/ppc/fpu_helper.c
> +++ b/target/ppc/fpu_helper.c
> @@ -403,7 +403,7 @@ void helper_fpscr_clrbit(CPUPPCState *env, uint32_t bit)
> if (prev == 1) {
> switch (bit) {
> case FPSCR_RN1:
> - case FPSCR_RN:
> + case FPSCR_RN0:
> fpscr_set_rounding_mode(env);
> break;
> case FPSCR_VXSNAN:
> @@ -557,7 +557,7 @@ void helper_fpscr_setbit(CPUPPCState *env, uint32_t bit)
> }
> break;
> case FPSCR_RN1:
> - case FPSCR_RN:
> + case FPSCR_RN0:
> fpscr_set_rounding_mode(env);
> break;
> default:
> diff --git a/target/ppc/translate/fp-impl.inc.c
> b/target/ppc/translate/fp-impl.inc.c
> index 9dcff94..7cd9d8d 100644
> --- a/target/ppc/translate/fp-impl.inc.c
> +++ b/target/ppc/translate/fp-impl.inc.c
> @@ -617,6 +617,28 @@ static void gen_mffs(DisasContext *ctx)
> tcg_temp_free_i64(t0);
> }
>
> +/* mffsl */
> +static void gen_mffsl(DisasContext *ctx)
> +{
> + TCGv_i64 t0;
> +
> + if (unlikely(!(ctx->insns_flags2 & PPC2_ISA300))) {
> + return gen_mffs(ctx);
> + }
> +
> + if (unlikely(!ctx->fpu_enabled)) {
> + gen_exception(ctx, POWERPC_EXCP_FPU);
> + return;
> + }
> + t0 = tcg_temp_new_i64();
> + gen_reset_fpstatus();
> + tcg_gen_extu_tl_i64(t0, cpu_fpscr);
> + /* Mask everything except mode, status, and enables. */
> + tcg_gen_andi_i64(t0, t0, FP_MODE | FP_STATUS | FP_ENABLES);
> + set_fpr(rD(ctx->opcode), t0);
> + tcg_temp_free_i64(t0);
> +}
> +
> /* mtfsb0 */
> static void gen_mtfsb0(DisasContext *ctx)
> {
> diff --git a/target/ppc/translate/fp-ops.inc.c
> b/target/ppc/translate/fp-ops.inc.c
> index 621f6bf..88ebc25 100644
> --- a/target/ppc/translate/fp-ops.inc.c
> +++ b/target/ppc/translate/fp-ops.inc.c
> @@ -104,7 +104,9 @@ GEN_HANDLER_E(fcpsgn, 0x3F, 0x08, 0x00, 0x00000000,
> PPC_NONE, PPC2_ISA205),
> GEN_HANDLER_E(fmrgew, 0x3F, 0x06, 0x1E, 0x00000001, PPC_NONE, PPC2_VSX207),
> GEN_HANDLER_E(fmrgow, 0x3F, 0x06, 0x1A, 0x00000001, PPC_NONE, PPC2_VSX207),
> GEN_HANDLER(mcrfs, 0x3F, 0x00, 0x02, 0x0063F801, PPC_FLOAT),
> -GEN_HANDLER(mffs, 0x3F, 0x07, 0x12, 0x001FF800, PPC_FLOAT),
> +GEN_HANDLER_E_2(mffs, 0x3F, 0x07, 0x12, 0x00, 0x00000000, PPC_FLOAT,
> PPC_NONE),
> +GEN_HANDLER_E_2(mffsl, 0x3F, 0x07, 0x12, 0x18, 0x00000000, PPC_FLOAT,
> + PPC2_ISA300),
> GEN_HANDLER(mtfsb0, 0x3F, 0x06, 0x02, 0x001FF800, PPC_FLOAT),
> GEN_HANDLER(mtfsb1, 0x3F, 0x06, 0x01, 0x001FF800, PPC_FLOAT),
> GEN_HANDLER(mtfsf, 0x3F, 0x07, 0x16, 0x00000000, PPC_FLOAT),
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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