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Re: [Qemu-devel] [PATCH] target-mips: fix multiplication in mipsdsp_rndq
From: |
Aurelien Jarno |
Subject: |
Re: [Qemu-devel] [PATCH] target-mips: fix multiplication in mipsdsp_rndq15_mul_q15_q15 |
Date: |
Sun, 28 Jul 2013 18:28:48 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Thu, May 23, 2013 at 07:37:53PM +0200, Petar Jovanovic wrote:
> From: Petar Jovanovic <address@hidden>
>
> Multiplication of Q15 fractional halfword vectors was incorrect in the
> previous implementation of mipsdsp_rndq15_mul_q15_q15. It failed to take
> element signs into account. This change fixes it, and it adds a test case
> for it.
>
> The change also removes unnecessary cast in the function
> mipsdsp_mul_q15_q15_overflowflag21().
>
> Signed-off-by: Petar Jovanovic <address@hidden>
> ---
> target-mips/dsp_helper.c | 4 ++--
> tests/tcg/mips/mips32-dsp/mulq_rs_ph.c | 19 ++++++++++++++++++-
> 2 files changed, 20 insertions(+), 3 deletions(-)
>
> diff --git a/target-mips/dsp_helper.c b/target-mips/dsp_helper.c
> index 4116de9..c718a78 100644
> --- a/target-mips/dsp_helper.c
> +++ b/target-mips/dsp_helper.c
> @@ -390,7 +390,7 @@ static inline int32_t
> mipsdsp_mul_q15_q15_overflowflag21(uint16_t a, uint16_t b,
> temp = 0x7FFFFFFF;
> set_DSPControl_overflow_flag(1, 21, env);
> } else {
> - temp = ((int32_t)(int16_t)a * (int32_t)(int16_t)b) << 1;
> + temp = ((int16_t)a * (int16_t)b) << 1;
> }
>
> return temp;
> @@ -622,7 +622,7 @@ static inline int16_t mipsdsp_rndq15_mul_q15_q15(uint16_t
> a, uint16_t b,
> temp = 0x7FFF0000;
> set_DSPControl_overflow_flag(1, 21, env);
> } else {
> - temp = (a * b) << 1;
> + temp = ((int16_t)a * (int16_t)b) << 1;
> temp = temp + 0x00008000;
> }
>
> diff --git a/tests/tcg/mips/mips32-dsp/mulq_rs_ph.c
> b/tests/tcg/mips/mips32-dsp/mulq_rs_ph.c
> index c720603..370c2a8 100644
> --- a/tests/tcg/mips/mips32-dsp/mulq_rs_ph.c
> +++ b/tests/tcg/mips/mips32-dsp/mulq_rs_ph.c
> @@ -12,7 +12,24 @@ int main()
> resultdsp = 1;
>
> __asm
> - ("mulq_rs.ph %0, %2, %3\n\t"
> + ("wrdsp $0\n\t"
> + "mulq_rs.ph %0, %2, %3\n\t"
> + "rddsp %1\n\t"
> + : "=r"(rd), "=r"(dsp)
> + : "r"(rs), "r"(rt)
> + );
> + dsp = (dsp >> 21) & 0x01;
> + assert(rd == result);
> + assert(dsp == resultdsp);
> +
> + rs = 0x80011234;
> + rt = 0x80024321;
> + result = 0x7FFD098C;
> + resultdsp = 0;
> +
> + __asm
> + ("wrdsp $0\n\t"
> + "mulq_rs.ph %0, %2, %3\n\t"
> "rddsp %1\n\t"
> : "=r"(rd), "=r"(dsp)
> : "r"(rs), "r"(rt)
Thanks, applied, sorry for the delay.
--
Aurelien Jarno GPG: 1024D/F1BCDB73
address@hidden http://www.aurel32.net