Re: [Qemu-devel] [PATCH v2 2/7] target/m68k: add fmovecr

["Philippe Mathieu-Daudé" <f4bug@amsat.org>]

On 06/27/2017 02:58 PM, Laurent Vivier wrote:
> Le 27/06/2017 à 17:45, Philippe Mathieu-Daudé a écrit :
>>> +static const floatx80 fpu_rom[128] = {
>>> +    [0x00] = floatx80_pi,                                   /* Pi */
>>> +    [0x0b] = make_floatx80(0x3ffd, 0x9a209a84fbcff798ULL),  /*
>>> Log10(2) */
>>> +    [0x0c] = make_floatx80(0x4000, 0xadf85458a2bb4a9aULL),  /*
>>> e        */
>>> +    [0x0d] = make_floatx80(0x3fff, 0xb8aa3b295c17f0bcULL),  /*
>>> Log2(e)  */
>>> +    [0x0e] = make_floatx80(0x3ffd, 0xde5bd8a937287195ULL),  /*
>>> Log10(e) */
>>> +    [0x0f] = floatx80_zero,                                 /*
>>> Zero     */
>>> +    [0x30] = floatx80_ln2,                                  /*
>>> ln(2)    */
>>> +    [0x31] = make_floatx80(0x4000, 0x935d8dddaaa8ac17ULL),  /*
>>> ln(10)   */
>>> +    [0x32] = floatx80_one,                                  /*
>>> 10^0     */
>>> +    [0x33] = make_floatx80(0x4002, 0xa000000000000000ULL),  /*
>>> 10^1     */
>>> +    [0x34] = make_floatx80(0x4005, 0xc800000000000000ULL),  /*
>>> 10^2     */
>>> +    [0x35] = make_floatx80(0x400c, 0x9c40000000000000ULL),  /*
>>> 10^4     */
>>> +    [0x36] = make_floatx80(0x4019, 0xbebc200000000000ULL),  /*
>>> 10^8     */
>>> +    [0x37] = make_floatx80(0x4034, 0x8e1bc9bf04000000ULL),  /*
>>> 10^16    */
>>> +    [0x38] = make_floatx80(0x4069, 0x9dc5ada82b70b59eULL),  /*
>>> 10^32    */
>>> +    [0x39] = make_floatx80(0x40d3, 0xc2781f49ffcfa6d5ULL),  /*
>>> 10^64    */
>>> +    [0x3a] = make_floatx80(0x41a8, 0x93ba47c980e98ce0ULL),  /*
>>> 10^128   */
>>> +    [0x3b] = make_floatx80(0x4351, 0xaa7eebfb9df9de8eULL),  /*
>>> 10^256   */
>>> +    [0x3c] = make_floatx80(0x46a3, 0xe319a0aea60e91c7ULL),  /*
>>> 10^512   */
>>> +    [0x3d] = make_floatx80(0x4d48, 0xc976758681750c17ULL),  /*
>>> 10^1024  */
>>> +    [0x3e] = make_floatx80(0x5a92, 0x9e8b3b5dc53d5de5ULL),  /*
>>> 10^2048  */
>>> +    [0x3f] = make_floatx80(0x7525, 0xc46052028a20979bULL),  /*
>>> 10^4096  */ +};
>>> +
>>>   int32_t HELPER(reds32)(CPUM68KState *env, FPReg *val)
>>>   {
>>>       return floatx80_to_int32(val->d, &env->fp_status);
>>> @@ -204,3 +229,8 @@ void HELPER(ftst)(CPUM68KState *env, FPReg *val)
>>>       }
>>>       env->fpsr = (env->fpsr & ~FPSR_CC_MASK) | cc;
>>>   }
>>> +
>>> +void HELPER(fconst)(CPUM68KState *env, FPReg *val, uint32_t offset)
>>> +{
>>> +    val->d = fpu_rom[offset];
>>
>> For offset not declared in fpu_rom (0x1..0xa, 0x10..0x2f, 0x40..0x7f),
>> this will return floatx80_zero, is this correct?
> 
> yes, according to the doc:
> 
> The values contained at offsets other than those defined above are
> reserved for the use of Motorola and may be different on various mask
> sets of the floating-point coprocessor. These undefined values yield the
> value 0.0 in the M68040FPSP

can you add this comment before/in the fpu_rom array please?