Before revision: iAPX432 0 stack of 6 Stack machine 16-bit x86 6 stack of 8 (if FP present) The 8086/8088, 80186/80188, and 80286 processors, if provided an 8087, 80187 or 80287 co-processor for floating-point operations, support an 80-bit wide, 8 deep register stack with some instructions able to use registers relative to the top of the stack as operands; without a co-processor, no floating-point registers are supported.
After revision: iAPX432 0 stack of 8 Stack machine 16-bit x86 6 stack of 8 (if FP present) The 8086/8088, 80186/80188, and 80286 processors, if provided an 8087, 80187 or 80287 co-processor for floating-point operations, support an 80-bit wide, 8 deep register stack with some instructions able to use registers relative to the top of the stack as operands; without a co-processor, no floating-point registers are supported.