[Qemu-devel] [PATCH] target-mips: Clean up microMIPS32 major opcode

[Qemu-devel] [PATCH] target-mips: Clean up microMIPS32 major opcode

[陳韋任 (Wei-Ren Chen)]

Hi all,

  I check MIPS microMIPS manual [1], and found the major opcode might be
wrong. I add a comment to explicitly indicate what manual I am refering
to, and according that manual I remove some microMIPS32 major opcodes.
Major opcode 0x1f is reserved, so I just remove it. As for others, like
0x16, 0x17, 0x36 and 0x37, they are for higher-order MIPS ISA level or
new revision of this microMIPS architecture. Since they are not appear
in the manual I refer to, I just remove them as well.

  Please review, thanks.   
  
[1] http://www.mips.com/products/architectures/micromips/#specifications

    MIPS Architecture for Programmers Volume II-B:
      The microMIPS32 Instruction Set (Revision 3.05)
    
    MD00582-2B-microMIPS-AFP-03.05.pdf

Signed-off-by: Chen Wei-Ren <chenwj@iis.sinica.edu.tw>
---
 target-mips/translate.c |   16 ++++++++++------
 1 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/target-mips/translate.c b/target-mips/translate.c
index f6fc0c2..b57da24 100644
--- a/target-mips/translate.c
+++ b/target-mips/translate.c
@@ -10241,7 +10241,15 @@ static int decode_mips16_opc (CPUMIPSState *env, DisasContext *ctx,
 
 /* microMIPS extension to MIPS32 */
 
-/* microMIPS32 major opcodes */
+/*
+ * microMIPS32 major opcodes
+ *
+ * MIPS Architecture for Programmers Volume II-B:
+ *   The microMIPS32 Instruction Set (Revision 3.05)
+ *
+ * Table 6.2 microMIPS32 Encoding of Major Opcode Field
+ *
+ */
 
 enum {
     POOL32A = 0x00,
@@ -10268,9 +10276,8 @@ enum {
     POOL16D = 0x13,
     ORI32 = 0x14,
     POOL32F = 0x15,
-    POOL32S = 0x16,
-    DADDIU32 = 0x17,
 
+    /* 0x1f is reserved */
     POOL32C = 0x18,
     LWGP16 = 0x19,
     LW16 = 0x1a,
@@ -10278,7 +10285,6 @@ enum {
     XORI32 = 0x1c,
     JALS32 = 0x1d,
     ADDIUPC = 0x1e,
-    POOL48A = 0x1f,
 
     /* 0x20 is reserved */
     RES_20 = 0x20,
@@ -10307,8 +10313,6 @@ enum {
     B16 = 0x33,
     ANDI32 = 0x34,
     J32 = 0x35,
-    SD32 = 0x36,
-    LD32 = 0x37,
 
     /* 0x38 and 0x39 are reserved */
     RES_38 = 0x38,
-- 
1.7.3.4

Re: [Qemu-devel] [PATCH] target-mips: Clean up microMIPS32 major opcode

[Johnson, Eric]

Hi Chen,

Please only remove the POOL48A opcode.

The others are documented in the microMIPS64 Instruction Set manual ( http://www.mips.com/secure-download/index.dot?product_name=/auth/MD00087-2B-MIPS64BIS-AFP-03.51.pdf ).  See http://www.mips.com/products/architectures/mips64/ for other relavent docs.

Instead of removing them please surround the POOL32S, DADDIU32, SD32, and LD32 opcodes with
#if defined(TARGET_MIPS64)

-Eric

> -----Original Message-----
> From: qemu-devel-bounces+ericj=mips.com@nongnu.org [mailto:qemu-devel-
> bounces+ericj=mips.com@nongnu.org] On Behalf Of ??? (Wei-Ren Chen)
> Sent: Wednesday, November 14, 2012 6:15 PM
> To: qemu-devel@nongnu.org; qemu-trivial@nongnu.org
> Cc: chenwj@cs.nctu.edu.tw; Jia Liu; Aurelien Jarno
> Subject: [Qemu-devel] [PATCH] target-mips: Clean up microMIPS32 major
> opcode
> 
> Hi all,
> 
>   I check MIPS microMIPS manual [1], and found the major opcode might be
> wrong. I add a comment to explicitly indicate what manual I am refering
> to, and according that manual I remove some microMIPS32 major opcodes.
> Major opcode 0x1f is reserved, so I just remove it. As for others, like
> 0x16, 0x17, 0x36 and 0x37, they are for higher-order MIPS ISA level or
> new revision of this microMIPS architecture. Since they are not appear
> in the manual I refer to, I just remove them as well.
> 
>   Please review, thanks.
> 
> [1] http://www.mips.com/products/architectures/micromips/#specifications
> 
>     MIPS Architecture for Programmers Volume II-B:
>       The microMIPS32 Instruction Set (Revision 3.05)
> 
>     MD00582-2B-microMIPS-AFP-03.05.pdf
> 
> Signed-off-by: Chen Wei-Ren <chenwj@iis.sinica.edu.tw>
> ---
>  target-mips/translate.c |   16 ++++++++++------
>  1 files changed, 10 insertions(+), 6 deletions(-)
> 
> diff --git a/target-mips/translate.c b/target-mips/translate.c
> index f6fc0c2..b57da24 100644
> --- a/target-mips/translate.c
> +++ b/target-mips/translate.c
> @@ -10241,7 +10241,15 @@ static int decode_mips16_opc (CPUMIPSState *env,
> DisasContext *ctx,
> 
>  /* microMIPS extension to MIPS32 */
> 
> -/* microMIPS32 major opcodes */
> +/*
> + * microMIPS32 major opcodes
> + *
> + * MIPS Architecture for Programmers Volume II-B:
> + *   The microMIPS32 Instruction Set (Revision 3.05)
> + *
> + * Table 6.2 microMIPS32 Encoding of Major Opcode Field
> + *
> + */
> 
>  enum {
>      POOL32A = 0x00,
> @@ -10268,9 +10276,8 @@ enum {
>      POOL16D = 0x13,
>      ORI32 = 0x14,
>      POOL32F = 0x15,
> -    POOL32S = 0x16,
> -    DADDIU32 = 0x17,
> 
> +    /* 0x1f is reserved */
>      POOL32C = 0x18,
>      LWGP16 = 0x19,
>      LW16 = 0x1a,
> @@ -10278,7 +10285,6 @@ enum {
>      XORI32 = 0x1c,
>      JALS32 = 0x1d,
>      ADDIUPC = 0x1e,
> -    POOL48A = 0x1f,
> 
>      /* 0x20 is reserved */
>      RES_20 = 0x20,
> @@ -10307,8 +10313,6 @@ enum {
>      B16 = 0x33,
>      ANDI32 = 0x34,
>      J32 = 0x35,
> -    SD32 = 0x36,
> -    LD32 = 0x37,
> 
>      /* 0x38 and 0x39 are reserved */
>      RES_38 = 0x38,
> --
> 1.7.3.4

Re: [Qemu-devel] [PATCH] target-mips: Clean up microMIPS32 major opcode

[陳韋任 (Wei-Ren Chen)]

On Thu, Nov 15, 2012 at 02:34:31AM +0000, Johnson, Eric wrote:
> Hi Chen,
> 
> Please only remove the POOL48A opcode.
> 
> The others are documented in the microMIPS64 Instruction Set manual ( http://www.mips.com/secure-download/index.dot?product_name=/auth/MD00087-2B-MIPS64BIS-AFP-03.51.pdf ).  See http://www.mips.com/products/architectures/mips64/ for other relavent docs.
> 
> Instead of removing them please surround the POOL32S, DADDIU32, SD32, and LD32 opcodes with
> #if defined(TARGET_MIPS64)
 
  Just want to make sure I am reading the right manual, are you refering
to [1] or [2]? The link you gave me is about MIPS64 not microMIPS64, I 
am not sure which one I should look into. I can find DADDIU, SD, and LD
in [1] and [2], all *without* 32 suffix. Should I change their name?
I cannot find POOL32S in both document, would you like to point it out?
Thanks.

Regards,
chenwj

[1] MIPS Architecture For Programmers
      Volume I-B: Introduction to the microMIPS64 Architecture

    MD00743-2B-microMIPS64INT-AFP-03.02.pdf
 
[2] MIPS Architecture For Programmers
      Volume II-A: The MIPS64 Instruction Set

    MD00087-2B-MIPS64BIS-AFP-03.51.pdf

-- 
Wei-Ren Chen (陳韋任)
Computer Systems Lab, Institute of Information Science,
Academia Sinica, Taiwan (R.O.C.)
Tel:886-2-2788-3799 #1667
Homepage: http://people.cs.nctu.edu.tw/~chenwj

Re: [Qemu-devel] [PATCH] target-mips: Clean up microMIPS32 major opcode

[Johnson, Eric]

Hi Chen,

Sorry I must have made a copy paste error.  I access the documents internally. I'll double check the link tomorrow.

The document I referenced is the MIPS64 not the microMIPS64.

Do not change the names. The LD32 and SD32 are microMIPS specific. The assembler LD and SD opcodes work for either MIPS64 or microMIPS64.

Eric

On Nov 14, 2012, at 7:27 PM, "陳韋任 (Wei-Ren Chen)" <chenwj@iis.sinica.edu.tw> wrote:

> On Thu, Nov 15, 2012 at 02:34:31AM +0000, Johnson, Eric wrote:
>> Hi Chen,
>> 
>> Please only remove the POOL48A opcode.
>> 
>> The others are documented in the microMIPS64 Instruction Set manual ( http://www.mips.com/secure-download/index.dot?product_name=/auth/MD00087-2B-MIPS64BIS-AFP-03.51.pdf ).  See http://www.mips.com/products/architectures/mips64/ for other relavent docs.
>> 
>> Instead of removing them please surround the POOL32S, DADDIU32, SD32, and LD32 opcodes with
>> #if defined(TARGET_MIPS64)
> 
>  Just want to make sure I am reading the right manual, are you refering
> to [1] or [2]? The link you gave me is about MIPS64 not microMIPS64, I 
> am not sure which one I should look into. I can find DADDIU, SD, and LD
> in [1] and [2], all *without* 32 suffix. Should I change their name?
> I cannot find POOL32S in both document, would you like to point it out?
> Thanks.
> 
> Regards,
> chenwj
> 
> [1] MIPS Architecture For Programmers
>      Volume I-B: Introduction to the microMIPS64 Architecture
> 
>    MD00743-2B-microMIPS64INT-AFP-03.02.pdf
> 
> [2] MIPS Architecture For Programmers
>      Volume II-A: The MIPS64 Instruction Set
> 
>    MD00087-2B-MIPS64BIS-AFP-03.51.pdf
> 
> -- 
> Wei-Ren Chen (陳韋任)
> Computer Systems Lab, Institute of Information Science,
> Academia Sinica, Taiwan (R.O.C.)
> Tel:886-2-2788-3799 #1667
> Homepage: http://people.cs.nctu.edu.tw/~chenwj

Re: [Qemu-devel] [PATCH] target-mips: Clean up microMIPS32 major opcode

[陳韋任 (Wei-Ren Chen)]

On Thu, Nov 15, 2012 at 04:01:32AM +0000, Johnson, Eric wrote:
> Hi Chen,
> 
> Sorry I must have made a copy paste error.  I access the documents internally. I'll double check the link tomorrow.
> 
> The document I referenced is the MIPS64 not the microMIPS64.
> 
> Do not change the names. The LD32 and SD32 are microMIPS specific. The assembler LD and SD opcodes work for either MIPS64 or microMIPS64.

  O.K., thanks for the help. :)

  How about DADDIU32, should I keep the 32 suffix, too?
I still can't find where POOL32S is.

Regards,
chenwj

-- 
Wei-Ren Chen (陳韋任)
Computer Systems Lab, Institute of Information Science,
Academia Sinica, Taiwan (R.O.C.)
Tel:886-2-2788-3799 #1667
Homepage: http://people.cs.nctu.edu.tw/~chenwj

Re: [Qemu-devel] [PATCH] target-mips: Clean up microMIPS32 major opcode

[Johnson, Eric]

> -----Original Message-----
> From: 陳韋任 (Wei-Ren Chen) [mailto:chenwj@iis.sinica.edu.tw]
> Sent: Wednesday, November 14, 2012 9:51 PM
> To: Johnson, Eric
> Cc: qemu-devel@nongnu.org; qemu-trivial@nongnu.org; Jia Liu; Aurelien
> Jarno
> Subject: Re: [Qemu-devel] [PATCH] target-mips: Clean up microMIPS32 major
> opcode
> 
> On Thu, Nov 15, 2012 at 04:01:32AM +0000, Johnson, Eric wrote:
> > Hi Chen,
> >
> > Sorry I must have made a copy paste error.  I access the documents
> internally. I'll double check the link tomorrow.
> >
> > The document I referenced is the MIPS64 not the microMIPS64.
> >
> > Do not change the names. The LD32 and SD32 are microMIPS specific. The
> assembler LD and SD opcodes work for either MIPS64 or microMIPS64.
> 
>   O.K., thanks for the help. :)
> 
>   How about DADDIU32, should I keep the 32 suffix, too?
> I still can't find where POOL32S is.
> 
> Regards,
> chenwj

The only opcode on the list that is incorrect is the POOL48A opcode.  It should be removed.  If the others are removed or renamed, I or someone else would just have to fix them at some point in the future.

It seems the microMIPS64 Instruction Set manual is not one the external website.  I'll ask about that.

-Eric

Re: [Qemu-devel] [PATCH] target-mips: Clean up microMIPS32 major opcode

[Aurelien Jarno]

On Thu, Nov 15, 2012 at 02:34:31AM +0000, Johnson, Eric wrote:
> Hi Chen,
> 
> Please only remove the POOL48A opcode.
> 
> The others are documented in the microMIPS64 Instruction Set manual ( http://www.mips.com/secure-download/index.dot?product_name=/auth/MD00087-2B-MIPS64BIS-AFP-03.51.pdf ).  See http://www.mips.com/products/architectures/mips64/ for other relavent docs.
> 
> Instead of removing them please surround the POOL32S, DADDIU32, SD32, and LD32 opcodes with
> #if defined(TARGET_MIPS64)
> 

I don't think a #if is necessary there, this makes the code more
difficult to read, while it doesn't change anything on the generated
code.

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net

Re: [Qemu-devel] [PATCH] target-mips: Clean up microMIPS32 major opcode

[Johnson, Eric]

> -----Original Message-----
> From: Aurelien Jarno [mailto:aurelien@aurel32.net]
> Sent: Thursday, November 15, 2012 6:04 AM
> To: Johnson, Eric
> Cc: 陳韋任 (Wei-Ren Chen); qemu-devel@nongnu.org; qemu-trivial@nongnu.org;
> chenwj@cs.nctu.edu.tw; Jia Liu
> Subject: Re: [Qemu-devel] [PATCH] target-mips: Clean up microMIPS32 major
> opcode
> 
> On Thu, Nov 15, 2012 at 02:34:31AM +0000, Johnson, Eric wrote:
> > Hi Chen,
> >
> > Please only remove the POOL48A opcode.
> >
> > The others are documented in the microMIPS64 Instruction Set manual (
> http://www.mips.com/secure-download/index.dot?product_name=/auth/MD00087-
> 2B-MIPS64BIS-AFP-03.51.pdf ).  See
> http://www.mips.com/products/architectures/mips64/ for other relavent
> docs.
> >
> > Instead of removing them please surround the POOL32S, DADDIU32, SD32,
> and LD32 opcodes with
> > #if defined(TARGET_MIPS64)
> >
> 
> I don't think a #if is necessary there, this makes the code more
> difficult to read, while it doesn't change anything on the generated
> code.

Agreed.

-Eric