tailieunhanh - Giáo trình Vi điều khiển - Phụ lục 4: Mô tả tập lệnh

ACALL addr11: Function: Absolute Call Description: ACALL unconditionally calls a subroutine located at the indicated address. The instruction increments the PC twice to obtain the address of the following instruction, then pushes the 16-bit result onto the stack (low-order byte first) and increments the Stack Pointer twice. The destination address is obtained by successively concatenating the five high-order bits of the incremented PC, opcode bits 7 through 5, and the second byte of the instruction. . | Giáo trình Vi điều khiển Phu luc 4 - Mo ta tap lenh Phụ lục 4 MÔ TẢ TẬP LỆNH 1. ACALL addr11 Function Absolute Call Description ACALL unconditionally calls a subroutine located at the indicated address. The instruction increments the PC twice to obtain the address of the following instruction then pushes the 16-bit result onto the stack low-order byte first and increments the Stack Pointer twice. The destination address is obtained by successively concatenating the five high-order bits of the incremented PC opcode bits 7 through 5 and the second byte of the instruction. The subroutine called must therefore start within the same 2 K block of the program memory as the first byte of the instruction following ACALL. No flags are affected. Example Initially SP equals 07H. The label SUBRTN is at program memory location 0345 H. After executing the following instruction ACALL SUBRTN at location 0123H SP contains 09H internal RAM locations 08H and 09H will contain 25H and 01H respectively and the PC contains 0345H. Bytes 2 Cycles 2 Encoding . A10 A9 A8 1 0 0 0 1 A7 A6 A5 A4 A3 A2 A1 A0 Operation ACALL PC PC 2 SP SP 1 SP PC7-0 SP SP 1 SP PC15-8 PC10-0 page address 2. ADD A src-byte Function Add Description ADD adds the byte variable indicated to the Accumulator leaving the result in the Accumulator. The carry and auxiliary-carry flags are set respectively if there is a carry-out from bit 7 or bit 3 and cleared otherwise. When adding unsigned integers the carry flag indicates an overflow occurred. OV is set if there is a carry-out of bit 6 but not out of bit 7 or a carry-out of bit 7 but not bit 6 otherwise OV is cleared. When adding signed integers OV indicates a negative number produced as the sum of two positive operands or a positive sum from two negative operands. Four source operand addressing modes are allowed register direct register-indirect or immediate. Phạm Hùng Kim Khánh Trang 195 Giáo trình Vi điều khiển Phu lue 4 - Mô ta tâp lênh Example The Accumulator holds .