Cxbx-reloaded: Fix RtlUpperChar

[PatrickvL]

The Cxbx-Reloaded implementation of the RtlUpperChar kernel API fails

From https://github.com/Cxbx-Reloaded/xbox_kernel_test_suite/issues/38#issuecomment-386902660 :

Four input values are failing on Cxbx-R that pass on real hardware.

0x013C - RtlUpperChar: Tests Starting
Test FAILED. Input = ''(0x9a), result = ''(0x8a), expected =''(0x9a)
Test FAILED. Input = ''(0x9c), result = ''(0x8c), expected =''(0x9c)
Test FAILED. Input = ''(0x9e), result = ''(0x8e), expected =''(0x9e)
Test FAILED. Input = ''(0xff), result = ''(0x9f), expected ='?'(0x3f)
0x013C - RtlUpperChar: One or more tests FAILED

Fix this so that the tests succeed

[x1nixmzeng]

If the behaviour is actually different from Windows then we could literally use expected_outputs as a lookup table for Cxbx. Source is:

https://github.com/Cxbx-Reloaded/xbox_kernel_test_suite/blob/42f59b81a80edc3443b2dc5bb05fc19f821fb42d/rtl_tests.c#L1021-L1038

Although I would not expect 0xFF to return 0x3F - that looks like it could be a logging issue?

[PatrickvL]

By all means, use that approach (or anyone wanting to spend some time improving our kernel)

[Fisherman166]

It is odd but 0xFF does return 0x3F when running on my NTSC Xbox.

[LukeUsher]

I wonder how the ReactOS implementation (or even the Xenia implementation) fares, might be worth comparing them, no point re-implementing the wheel again if one of these implementations can be suitable

[PatrickvL]

Well, if a simple lookup table can suffice then why not?

[x1nixmzeng]

xenia just works on the characters a to z

dword_result_t RtlUpperChar(dword_t in) {
  char c = in & 0xFF;
  if (c >= 'a' && c <= 'z') {
    return c ^ 0x20;
  }

  return c;
}
DECLARE_XBOXKRNL_EXPORT(RtlUpperChar, ExportTag::kImplemented);

I'll see what my Xbox outputs

[PatrickvL]

That'll be interesting

[x1nixmzeng]

I'm having issues getting certain types to log in NXDK so I re-wrote the test to dump the raw binary data.

CHAR x1[300];
memset(&x1, 0, 300);

CHAR x2[300];
memset(&x2, 0, 300);

for(int i = 0; i < 300; ++i )
{
    x1[i] = (CHAR)(i & 0xFF);
    x2[i] = RtlUpperChar(i);
}

print("dumping x1");
write_to_output_file(&x1, 300);
print("dumping x2");
write_to_output_file(&x2, 300);

for(int i = 0; i < 300; ++i )
{
  if( x1[i] != x2[i] )
     print("failed on %x", i);
}

Cxbx

0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F,
0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F,
0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0x3F,
0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F,
0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x5B, 0x5C, 0x5D, 0x5E, 0x5F,
0x60, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F,
0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x7B, 0x7C, 0x7D, 0x7E, 0x7F,
0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F,
0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x8A, 0x9B, 0x8C, 0x9D, 0x8E, 0x9F,
0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 0xA8, 0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF,
0xB0, 0xB1, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE, 0xBF,
0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF,
0xD0, 0xD1, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xDB, 0xDC, 0xDD, 0xDE, 0xDF,
0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF,
0xD0, 0xD1, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xF7, 0xD8, 0xD9, 0xDA, 0xDB, 0xDC, 0xDD, 0xDE, 0x9F

Xbox

0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F,
0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F,
0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0x3F,
0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F,
0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x5B, 0x5C, 0x5D, 0x5E, 0x5F,
0x60, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F,
0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x7B, 0x7C, 0x7D, 0x7E, 0x7F,
0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F,
0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0x9B, 0x9C, 0x9D, 0x9E, 0x9F,
0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 0xA8, 0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF,
0xB0, 0xB1, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE, 0xBF,
0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF,
0xD0, 0xD1, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xDB, 0xDC, 0xDD, 0xDE, 0xDF,
0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF,
0xD0, 0xD1, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xF7, 0xD8, 0xD9, 0xDA, 0xDB, 0xDC, 0xDD, 0xDE, 0x3F,

Differences

The same as what @Fisherman166 reported.

| Character | Cxbx Upper | Xbox Upper |
|---|---|---|
| 0x9a | 0x8a | 0x9a |
| 0x9c | 0x8c | 0x9c |
| 0x9e | 0x8e | 0x9e |
| 0xff | 0x9f | 0x3f |

:tada:

[PatrickvL]

Good detective work there!
This settles it then - toupper can't be used, and the obvious choice is to use the above as a lookup table