Q. Convention used to represent micro-operations?

The convention used to represent micro-operations is:

1.  Computer register names are designated by capital letters (sometimes followed by numerals) to denote its function. For illustration R1, R2 (General Purpose Registers), AR (Address Register), IR (Instruction Register) etc. 

2. Individual bits within a register are numbered from 0 (rightmost bit) to n-1 (leftmost bit) as shown in Figure below). Common ways of drawing block diagram of a computer register are displayed below. The name of 16-bit register is IR (Instruction Register) that is partitioned into two subfields in Figure D below). Bits 0 through 7 are assigned the symbol L (for Low byte) and bits 8 through 15 are assigned symbol H (for high byte). Symbol IR (L) refers to low-order byte and IR (H) refers to high-order byte.

Figure: Register Formats