
Semiconductor Group
133
Instruction Set
Unconditional Calls, Returns and Jumps
Unconditional calls, returns and jumps transfer control from the current value of the program
counter to the target address. Both direct and indirect transfers are supported.
– ACALL and LCALL push the address of the next instruction onto the stack and then transfer
control to the target address. ACALL is a 2-byte instruction used when the target address is
in the current 2K page. LCALL is a 3-byte instruction that addresses the full 64K program
space. In ACALL, immediate data (i.e. an 11-bit address field) is concatenated to the five most
significant bits of the PC (which is pointing to the next instruction). If ACALL is in the last 2
bytes of a 2K page then the call will be made to the next page since the PC will have been
incremented to the next instruction prior to execution.
– RET transfers control to the return address saved on the stack by a previous call operation
and decrements the SP register by two (2) to adjust the SP for the popped address.
– AJMP, LJMP and SJMP transfer control to the target operand. The operation of AJMP and
LJMP are analogous to ACALL and LCALL. The SJMP (short jump) instruction provides for
transfers within a 256-byte range centered about the starting address of the next instruction
(– 128 to + 127).
– JMP @A + DPTR performs a jump relative to the DPTR register. The operand in A is used as
the offset (0 - 255) to the address in the DPTR register. Thus, the effective destination for a
jump can be anywhere in the program memory space.
Conditional Jumps
Conditional jumps perform a jump contingent upon a specific condition. The destination will be
within a 256-byte range centered about the starting address of the next instruction (– 128 to + 127).
– JZ performs a jump if the accumulator is zero.
– JNZ performs a jump if the accumulator is not zero.
– JC performs a jump if the carry flag is set.
– JNC performs a jump if the carry flag is not set.
– JB performs a jump if the directly addressed bit is set.
– JNB performs a jump if the directly addressed bit is not set.
– JBC performs a jump if the directly addressed bit is set and then clears the directly addressed
bit.
– CJNE compares the first operand to the second operand and performs a jump if they are not
equal. CY is set if the first operand is less than the second operand; otherwise it is cleared.
Comparisons can be made between A and directly addressable bytes in internal data memory
or an immediate value and either A, a register in the selected register bank, or a register
indirectly addressable byte of the internal RAM.
– DJNZ decrements the source operand and returns the result to the operand. A jump is
performed if the result is not zero. The source operand of the DJNZ instruction may be any
directly addressable byte in the internal data memory. Either direct or register addressing may
be used to address the source operand.
Interrupt Returns
– RETI transfers control as RET does, but additionally enables interrupts of the current priority
level.
*
Содержание SAB 80515 Series
Страница 9: ...Semiconductor Group 9 Introduction Figure 1 2 Block Diagram ...
Страница 12: ...Semiconductor Group 12 Fundamental Structure Figure 2 1 Detailed Block Diagram ...
Страница 18: ...Semiconductor Group 18 Central Processing Unit Figure 3 1 Fetch Execute Sequence ...
Страница 22: ...Semiconductor Group 22 Memory Organization Figure 4 3 Mapping of the Lower Portion of the Internal Data Memory ...
Страница 30: ...Semiconductor Group 30 External Bus Interface Figure 5 1 a and b External Program Memory Execution ...
Страница 38: ...Semiconductor Group 38 On Chip Peripheral Components Figure 7 3 Output Driver Circuits of Ports 1 through 5 ...
Страница 59: ...Semiconductor Group 59 On Chip Peripheral Components Figure 7 16 a Functional Diagram Serial Interface Mode 0 ...
Страница 60: ...Semiconductor Group 60 On Chip Peripheral Components Figure 7 16 b Timing Diagram Serial Interface Mode 0 ...
Страница 61: ...Semiconductor Group 61 On Chip Peripheral Components Figure 7 17 a Functional Diagram Serial Interface Mode 1 ...
Страница 62: ...Semiconductor Group 62 On Chip Peripheral Components Figure 7 17 b Timing Diagram Serial Interface Mode 1 ...
Страница 73: ...Semiconductor Group 73 On Chip Peripheral Components Figure 7 25 A D Converter Block Diagram ...
Страница 83: ...Semiconductor Group 83 On Chip Peripheral Components Figure 7 33 a Timer 2 Block Diagram ...
Страница 111: ...Semiconductor Group 111 On Chip Peripheral Components Figure 7 54 Timing Diagram System Clock Output ...
Страница 113: ...Semiconductor Group 113 Interrupt System Figure 8 1 a Interrupt Structure of the SAB 80 C 515 80 C 535 ...
Страница 114: ...Semiconductor Group 114 Interrupt System Figure 8 1 b Interrupt Structure of the SAB 80 C 515 80 C 535 cont d ...
Страница 204: ...Semiconductor Group 204 Instruction Set XCH A Ri Operation XCH A Ri Bytes 1 Cycles 1 Encoding 1 1 0 0 0 1 1 i ...
Страница 215: ...Device Specifications Semiconductor Group 215 ...
Страница 217: ...Device Specifications Semiconductor Group 217 Pin Configuration P LCC 68 ...
Страница 219: ...Device Specifications Semiconductor Group 219 Logic Symbol ...
Страница 226: ...Device Specifications Semiconductor Group 226 Figure 1 Block Diagram ...
Страница 229: ...Device Specifications Semiconductor Group 229 Figure 2 Memory Address Spaces ...
Страница 239: ...Device Specifications Semiconductor Group 239 Figure 4 Block Diagram of the A D Converter ...
Страница 241: ...Device Specifications Semiconductor Group 241 Figure 5 Interrupt Request Sources ...
Страница 242: ...Device Specifications Semiconductor Group 242 Figure 6 Interrupt Priority Level Structure ...
Страница 268: ...Device Specifications Semiconductor Group 268 AC Testing Input Output Waveforms AC Testing Float Waveforms ...