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Re: [Qemu-devel] [PATCH 2/2] target-sh4: implement ftrv instruction
From: |
Aurelien Jarno |
Subject: |
Re: [Qemu-devel] [PATCH 2/2] target-sh4: implement ftrv instruction |
Date: |
Tue, 3 Feb 2009 21:28:24 +0100 |
User-agent: |
Mutt/1.5.18 (2008-05-17) |
On Fri, Nov 21, 2008 at 07:55:42PM +0000, Mans Rullgard wrote:
> This partially implements the ftrv instruction. It gives correct
> results under normal conditions. FPU exceptions are not correctly
> generated.
>
> Signed-off-by: Mans Rullgard <address@hidden>
> ---
> target-sh4/translate.c | 40 ++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 40 insertions(+), 0 deletions(-)
>
> diff --git a/target-sh4/translate.c b/target-sh4/translate.c
> index 2d6dfe6..9c2da41 100644
> --- a/target-sh4/translate.c
> +++ b/target-sh4/translate.c
> @@ -1694,6 +1694,46 @@ static void _decode_opc(DisasContext * ctx)
> tcg_temp_free_i64(fp);
> }
> return;
> + case 0xf0fd: /* ftrv XMTRX,FVn */
> + if ((ctx->opcode & 0x300) != 0x100)
> + break;
> + if (!(ctx->fpscr & FPSCR_PR)) {
> + TCGv fv[4];
> + TCGv fp;
> + int n = B11_8 & 0xc;
> + int i;
> +
> + /*
> + * NOTE: The values calculated here are likely to differ
> + * from hardware since the hardware sacrifices accuracy
> + * for speed in this instruction.
> + *
> + * FIXME: FPU exceptions are not correctly raised here.
> + */
> +
> + fp = tcg_temp_new();
> +
> + for (i = 0; i < 4; i++) {
> + fv[i] = tcg_temp_new();
> + tcg_gen_mov_i32(fv[i], cpu_fregs[n+i]);
> + }
> +
> + for (i = 0; i < 4; i++) {
> + gen_helper_fmul_FT(cpu_fregs[n+i], cpu_fregs[16+i], fv[0]);
> + gen_helper_fmul_FT(fp, cpu_fregs[20+i], fv[1]);
> + gen_helper_fadd_FT(cpu_fregs[n+i], cpu_fregs[n+i], fp);
> + gen_helper_fmul_FT(fp, cpu_fregs[24+i], fv[2]);
> + gen_helper_fadd_FT(cpu_fregs[n+i], cpu_fregs[n+i], fp);
> + gen_helper_fmul_FT(fp, cpu_fregs[28+i], fv[3]);
> + gen_helper_fadd_FT(cpu_fregs[n+i], cpu_fregs[n+i], fp);
> + }
> +
> + for (i = 0; i < 4; i++)
> + tcg_temp_free(fv[i]);
> + tcg_temp_free(fp);
> + return;
> + }
> + break;
> }
>
> fprintf(stderr, "unknown instruction 0x%04x at pc 0x%08x\n",
While this code probably produce the correct result, I am not sure it is
the best way to do it. It calls 28 times an helper, and uses 5 temp
variable. IMHO the ftrv should be implemented in an helper, called from
translate.c.
--
Aurelien Jarno GPG: 1024D/F1BCDB73
address@hidden http://www.aurel32.net
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