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WD16
The WD16 is a 16-bit microprocessor introduced by Western Digital in October 1976. It is based on the MCP-1600 chipset, a general-purpose design that was also used to implement the DEC LSI-11 low-end minicomputer and the Pascal MicroEngine processor. The three systems differed primarily in their microcode, giving each system a unique instruction set architecture (ISA).
The WD16 implements an extension of the PDP-11 instruction set architecture but is not machine code compatible with the PDP-11. The instruction set and microcoding were created by Dick Wilcox and Rich Notari. The WD16 is an example of orthogonal CISC architecture. Most two-operand instructions can operate memory-to-memory with any addressing mode and some instructions can result in up to ten memory accesses.
The WD16 is implemented in five 40-pin DIP packages. Maximum clock speed is 3.3 MHz. Its interface to memory is via a 16-bit multiplexed data/address bus.
The WD16 is best known for its use in Alpha Microsystems' AM-100 and AM-100/T processor boards. A prototype was demonstrated in 1977. As of 1981 there were at least 5,000 Alpha Micro computers based on the WD16. As late as 1982, WD16-based Alpha Micros were still being characterized as "supermicros." The WD16 was superseded by the Motorola 68000 in June 1982.
The CPU contains eight general-purpose 16-bit registers, R0 to R7. The registers can be used for any purpose with these exceptions: Register R7 is the program counter (PC). Although any register can be used as a stack pointer, R6 is the stack pointer (SP) used for hardware interrupts and traps. R0 is the count for the block transfer instructions.
The smallest unit of addressable and writable memory is the 8-bit byte. Bytes can also be held in the lower half of registers R0 through R5.
16-bit words are stored little-endian with least significant bytes at the lower address. Words are always aligned to even memory addresses. Words can be held in registers R0 through R7.
32-bit double words can only be stored in register pairs with the lower word being stored in the lower-numbered register. 32 bit values are used by MUL, DIV and some rotate and arithmetic shift instructions.
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WD16 AI simulator
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WD16
The WD16 is a 16-bit microprocessor introduced by Western Digital in October 1976. It is based on the MCP-1600 chipset, a general-purpose design that was also used to implement the DEC LSI-11 low-end minicomputer and the Pascal MicroEngine processor. The three systems differed primarily in their microcode, giving each system a unique instruction set architecture (ISA).
The WD16 implements an extension of the PDP-11 instruction set architecture but is not machine code compatible with the PDP-11. The instruction set and microcoding were created by Dick Wilcox and Rich Notari. The WD16 is an example of orthogonal CISC architecture. Most two-operand instructions can operate memory-to-memory with any addressing mode and some instructions can result in up to ten memory accesses.
The WD16 is implemented in five 40-pin DIP packages. Maximum clock speed is 3.3 MHz. Its interface to memory is via a 16-bit multiplexed data/address bus.
The WD16 is best known for its use in Alpha Microsystems' AM-100 and AM-100/T processor boards. A prototype was demonstrated in 1977. As of 1981 there were at least 5,000 Alpha Micro computers based on the WD16. As late as 1982, WD16-based Alpha Micros were still being characterized as "supermicros." The WD16 was superseded by the Motorola 68000 in June 1982.
The CPU contains eight general-purpose 16-bit registers, R0 to R7. The registers can be used for any purpose with these exceptions: Register R7 is the program counter (PC). Although any register can be used as a stack pointer, R6 is the stack pointer (SP) used for hardware interrupts and traps. R0 is the count for the block transfer instructions.
The smallest unit of addressable and writable memory is the 8-bit byte. Bytes can also be held in the lower half of registers R0 through R5.
16-bit words are stored little-endian with least significant bytes at the lower address. Words are always aligned to even memory addresses. Words can be held in registers R0 through R7.
32-bit double words can only be stored in register pairs with the lower word being stored in the lower-numbered register. 32 bit values are used by MUL, DIV and some rotate and arithmetic shift instructions.
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