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List:       qemu-s390x
Subject:    Re: [PATCH] target/s390x/translate: Fix RNSBG instruction
From:       Thomas Huth <thuth () redhat ! com>
Date:       2020-01-30 18:39:28
Message-ID: 0a3472ed-f6be-0118-fe24-a9710bc6ed05 () redhat ! com
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On 30/01/2020 14.45, David Hildenbrand wrote:
> On 30.01.20 14:34, Thomas Huth wrote:
>> RNSBG is handled via the op_rosbg() helper function. But RNSBG has
>> the opcode 0xEC54, i.e. 0x54 as second byte, while op_rosbg() currently
>> checks for 0x55. This seems to be a typo, fix it to use 0x54 instead,
>> so that op_rosbg() does not abort() anymore if a program uses RNSBG.
>>
>> I've checked with a simply test function that I now get the same results
>> with KVM and with TCG:
>>
>>  static void test_rnsbg(void)
>>  {
>> 	uint64_t r1, r2;
>>
>> 	r2 = 0xffff000000000000UL;
>> 	r1 = 0x123456789bdfaaaaUL;
>> 	asm volatile (" rnsbg %0,%1,12,61,16 " : "+r"(r1) : "r"(r2));
>>
>> 	printf("r1 afterwards: 0x%lx\n", r1);
>>  }
> 
> You could add a tcg test case for that :)

I already thought about it ... I'll have a try when I've got some spare
time.

 Thomas



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