instrs: Add support for undocumented instructions

Undocumented instruction are not decoded by default.

- SALC: undocumented in any recent manual and unsupported by newer
  Intel CPUs. Including as listed by [1,2].
- Undocumented FPU instructions: see [2].

[1]: http://www.rcollins.org/secrets/opcodes/SALC.html
[2]: https://github.com/xoreaxeaxeax/sandsifter/issues/33

instrs.txt

@@ -252,7 +252,7 @@ d3/6                  MC    GP     GP8    -      -      SHL
 d3/7                  MC    GP     GP8    -      -      SAR
 d4                    I     IMM    -      -      -      AAM ONLY32 SIZE_8
 d5                    I     IMM    -      -      -      AAD ONLY32 SIZE_8
-#d6 unused
+d6                    NP    -      -      -      -      SALC ONLY32 UNDOC
 d7                    NP    -      -      -      -      XLATB
 #d8-df FPU Escape
 e0                    D     IMM    -      -      -      LOOPNZ FORCE64 IMM_8
@@ -1357,8 +1357,11 @@ db/0r                 M     FPU    -      -      -      FCMOVNB
 db/1r                 M     FPU    -      -      -      FCMOVNE
 db/2r                 M     FPU    -      -      -      FCMOVNBE
 db/3r                 M     FPU    -      -      -      FCMOVNU
+dbe0                  NP    -      -      -      -      FENI8087_NOP UNDOC
+dbe1                  NP    -      -      -      -      FDISI8087_NOP UNDOC
 dbe2                  NP    -      -      -      -      FCLEX
 dbe3                  NP    -      -      -      -      FINIT
+dbe4                  NP    -      -      -      -      FSETPM287_NOP UNDOC
 db/5r                 M     FPU    -      -      -      FUCOMI
 db/6r                 M     FPU    -      -      -      FCOMI
 dc/0m                 M     MEM64  -      -      -      FADD ENC_SEPSZ
@@ -1371,6 +1374,8 @@ dc/6m                 M     MEM64  -      -      -      FDIV ENC_SEPSZ
 dc/7m                 M     MEM64  -      -      -      FDIVR ENC_SEPSZ
 dc/0r                 MA    FPU    FPU    -      -      FADD
 dc/1r                 MA    FPU    FPU    -      -      FMUL
+dc/2r                 MA    FPU    FPU    -      -      FCOM UNDOC
+dc/3r                 MA    FPU    FPU    -      -      FCOMP UNDOC
 dc/4r                 MA    FPU    FPU    -      -      FSUBR
 dc/5r                 MA    FPU    FPU    -      -      FSUB
 dc/6r                 MA    FPU    FPU    -      -      FDIVR
@@ -1410,6 +1415,7 @@ df/4m                 M     FPU    -      -      -      FBLD
 df/5m                 M     MEM64  -      -      -      FILD ENC_SEPSZ
 df/6m                 M     FPU    -      -      -      FBSTP
 df/7m                 M     MEM64  -      -      -      FISTP ENC_SEPSZ
+df/0r                 M     FPU    -      -      -      FFREEP UNDOC
 # FSTSW AX
 dfe0                  A     GP16   -      -      -      FSTSW
 df/5r                 AM    FPU    FPU    -      -      FUCOMIP

meson.build

@@ -35,6 +35,9 @@ endif
 if get_option('archmode') != 'only32'
   generate_args += ['--64']
 endif
+if get_option('with_undoc')
+  generate_args += ['--with-undoc']
+endif
 
 instr_data = custom_target('tables',
                            command: [python3, '@INPUT0@', '@INPUT1@', '@OUTPUT@'] + generate_args,

meson_options.txt

@@ -1 +1,2 @@
 option('archmode', type: 'combo', choices: ['both', 'only32', 'only64'])
+option('with_undoc', type: 'boolean', value: false)

parseinstrs.py

@@ -471,7 +471,7 @@ def encode_table(entries):
     for opcode, desc in entries:
         if desc.mnemonic[:9] == "RESERVED_":
             continue
-        if "ONLY32" in desc.flags or "UNDOC" in desc.flags:
+        if "ONLY32" in desc.flags:
             continue
 
         opsizes = {8} if "SIZE_8" in desc.flags else {16, 32, 64}
@@ -615,6 +615,7 @@ if __name__ == "__main__":
     parser = argparse.ArgumentParser()
     parser.add_argument("--32", dest="modes", action="append_const", const=32)
     parser.add_argument("--64", dest="modes", action="append_const", const=64)
+    parser.add_argument("--with-undoc", action="store_true")
     parser.add_argument("table", type=argparse.FileType('r'))
     parser.add_argument("decode_mnems", type=argparse.FileType('w'))
     parser.add_argument("decode_table", type=argparse.FileType('w'))
@@ -625,8 +626,10 @@ if __name__ == "__main__":
     entries = []
     for line in args.table.read().splitlines():
         if not line or line[0] == "#": continue
-        opcode_string, desc = tuple(line.split(maxsplit=1))
+        opcode_string, desc_string = tuple(line.split(maxsplit=1))
-        entries.append((Opcode.parse(opcode_string), InstrDesc.parse(desc)))
+        opcode, desc = Opcode.parse(opcode_string), InstrDesc.parse(desc_string)
+        if "UNDOC" not in desc.flags or args.with_undoc:
+            entries.append((opcode, desc))
 
     mnemonics = sorted({desc.mnemonic for _, desc in entries})