MIPS partial support for c.eq.d and friends

[wideglide]

It seems MIPS[32/64] bit has only partial support for the family of c.{eq,le,ge}.d instructions.

I'm testing on next 31af3c3

This version is supported:

$ ./cstool/cstool -d mips64 "32 C0 38 46"
 0  32 c0 38 46  c.eq.d $f24, $f24
        ID: 168 (c)
        op_count: 2
                operands[0].type: REG = f24
                operands[1].type: REG = f24
        Groups: stdenc notmips32r6 notmips64r6 fp64bit

These versions are unsupported:

$ ./cstool/cstool -d mips64 "32 02 20 46"
ERROR: invalid assembly code
$ ./cstool/cstool -d mips64 "32 03 20 46"
ERROR: invalid assembly code

$ ./cstool/cstool -v
cstool for Capstone Disassembler, v5.0.0
Capstone build: x86=1 arm=1 arm64=1 mips=1 ppc=1 sparc=1 sysz=1 xcore=1 m68k=1 tms320c64x=1 m680x=1 evm=1 wasm=1 mos65xx=1 bpf=1 riscv=1

But the are supported with llvm-mc-9:

$ echo "0x32 0xC0 0x38 0x46" | llvm-mc-9 -disassemble -triple=mips64el-linux-gnu
        .text
        c.eq.d  $f24, $f24
$ echo "0x32 0x02 0x20 0x46" | llvm-mc-9 -disassemble -triple=mips64el-linux-gnu
        .text
        c.eq.d  $fcc2, $f0, $f0

Similiar result for mips (32-bit):

$ echo "0x33 0x05 0x22 0x46" | llvm-mc-9 -disassemble -triple=mipsel-linux-gnu
        .text
        c.ueq.d $fcc5, $f0, $f2
$ ./cstool/cstool -d mips "3e 05 22 46"
ERROR: invalid assembly code
$ ./cstool/cstool -d mips "3e 00 22 46"
 0  3e 00 22 46  c.le.d $f0, $f2
        ID: 168 (c)
        op_count: 2
                operands[0].type: REG = f0
                operands[1].type: REG = f2
        Groups: stdenc notmips32r6 notmips64r6 notfp64bit

Excerpt from busybox:

.text:00000001200B8EF4 D0 FF 52 10                 beq     $v0, $s2, loc_1200B8E38
.text:00000001200B8EF8 01 00 10 24                 li      $s0, 1
.text:00000001200B8EFC 32 C0 38 46                 c.eq.d  $f24, $f24          <== OK
.text:00000001200B8F00 06 00 01 45                 bc1t    loc_1200B8F1C
.text:00000001200B8F04 32 02 20 46                 c.eq.d  $fcc2, $f0, $f0     <== ERROR
.text:00000001200B8F08 32 03 20 46                 c.eq.d  $fcc3, $f0, $f0
.text:00000001200B8F0C 01 00 10 24                 li      $s0, 1
.text:00000001200B8F10 01 80 0C 00                 movf    $s0, $zero, $fcc3