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[3] [48] It can perform as an 8-bit 8051, has 24-bit linear addressing, an 8-bit ALU, 8-bit instructions, 16-bit instructions, a limited set of 32-bit instructions, 16 8-bit registers, 16 16-bit registers (8 16-bit registers which do not share space with any 8-bit registers, and 8 16-bit registers which contain 2 8-bit registers per 16-bit ...
The Auxiliary Carry flag is set (to 1) if during an "add" operation there is a carry from the low nibble (lowest four bits) to the high nibble (upper four bits), or a borrow from the high nibble to the low nibble, in the low-order 8-bit portion, during a subtraction. Otherwise, if no such carry or borrow occurs, the flag is cleared or "reset ...
The last two bits are 11. P = 1111 0100 1. Arithmetic right shift. The product is 1111 0100, which is −12. The above-mentioned technique is inadequate when the multiplicand is the most negative number that can be represented (e.g. if the multiplicand has 4 bits then this value is −8). This is because then an overflow occurs when computing ...
For 8-bit integers the table of quarter squares will have 2 9 −1=511 entries (one entry for the full range 0..510 of possible sums, the differences using only the first 256 entries in range 0..255) or 2 9 −1=511 entries (using for negative differences the technique of 2-complements and 9-bit masking, which avoids testing the sign of ...
A conventional eight-bit byte is −127 10 to +127 10 with zero being either 00000000 (+0) or 11111111 (−0). To add two numbers represented in this system, one does a conventional binary addition, but it is then necessary to do an end-around carry: that is, add any resulting carry back into the resulting sum. [8]
The result should be 510 which is the 9-bit value 111111110 in binary. The 8 least significant bits always stored in the register would be 11111110 binary (254 decimal) but since there is carry out of bit 7 (the eight bit), the carry is set, indicating that the result needs 9 bits. The valid 9-bit result is the concatenation of the carry flag ...
When the bit numbering starts at zero for the least significant bit (LSb) the numbering scheme is called LSb 0. [1] This bit numbering method has the advantage that for any unsigned number the value of the number can be calculated by using exponentiation with the bit number and a base of 2. [2] The value of an unsigned binary integer is therefore
The 8051 microcontroller has two, a primary accumulator and a secondary accumulator, where the second is used by instructions only when multiplying (MUL AB) or dividing (DIV AB); the former splits the 16-bit result between the two 8-bit accumulators, whereas the latter stores the quotient on the primary accumulator A and the remainder in the ...