MMX instructions ....
MMX registers are noted:
MM0, MM1, ..., MM7
MMX registers and memory operands are always 64 bits long (8 bytes) but can operate on 1 Qword, 2 Dwords, 4 Words or 8 bytes.
When you find in the documentation: PADD (Add with wrap-around) for example, this instruction has actually 3 forms, one for bytes, one for words, and one for dWords; so that this mnemonic is extended to 3 forms in RosAsm:
PADD PADDB / PADDW / PADDDD
As usual, you can write more clearly:
P_AAD_B / ... , that could stand for 'Packed Addition on Bytes / ...
Each time an MMX instruction has several forms, if you do not specify any in the mnemonic, RosAsm will consider it to be the smallest possible one (P_ADD = P_ADD_B). If you do specify one for a mnemonic which has only one form (no need of any specifier), you won't get an error message, as far as your parameter specifier is fitting.
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