Output: after CPUID:

        EAX = 0000 0001 : OK, instruction supported
        EBX = 756e 6547 : 'uneG'
        EDX = 4965 6e69 : 'Ieni'
        ECX = 6c65 746e : 'letn'
        effectively the CPU says 'GenuineIntel'

Officially this returns a 'vendor string', which may indicate other than
Intel strings for OEMs.
The UMC U5S-33 returns 'UMC UMC UMC ' or ' UMC UMC UMC' (untested).