The "B' registers

The "B" register is very similar to the Accumulator in the sense that it may hold an 8-bit (1-byte) value. The "B" register is only used by two 8051 instructions: MUL AB and DIV AB. Thus, if there is need for quickly and easily multiply or divide A by another number, this may store the other number in "B" and make use of these two instructions. Aside from the MUL and DIV instructions, the "B" register is often used as yet another temporary storage register much like a ninth "R" register.

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