Bits representation

[gagachang]

Current spec. uses bit {bit start position}:{bit length} to represent a bit field.
I.e., The Zimte extension adds the MTE_MODE field (bit 34:2) to mseccfg.

Suggest to make the bit representation be consistent with the privileged spec.
I.e., Privileged spec uses bit {bit end position}:{bit start position} or bit {bit end position}-{bit start position}

Examples from privileged spec:

• The standard portions (bits 15:0) of registers sip and sie are formatted ...
• Instruction fetch addresses and load and store effective addresses, which are 64 bits, must have bits 63–39 all equal to bit 38,