450 Digital Design of Signal Processing Systems If (R4 0 ) jump R If (Re> 0 ) jump R Call subroutine Rs and return support Rito Rs are 8 bit registers. A branch address or subroutine address can be written in Rs using a load instruction. As given in the instruction set jump and subroutine instructions are developed to use the contents of Rs as address of the next instruction. The conditions are based on the content of R. Draw the RTL diagram of the datapath and micro programmed state machine. Show all the control signals. Specify the instruction format and size. The datapath should be optimal using only one carry propagate adder (CPA) by appropriately using a compression block to compress the number of operands to two. Exercise 10.8 Design a micro coded state machine based design, with the following features. 1. There are three register files, P, Q and R. Each register file has four 8 bit registers. 2. There is an adder and logic unit to perform addition, subtraction, AND, OR and XOR operations. 3. There is 264 deep micro code memory. 4. The state machine supports the following instructions: (a) Load constant into ith register of Por Q: P;=const Qi=const (b) Perform any arithmetic or logic operation given in (2) on operands in register files Pand Q, and store the result in register file R: R;=P; op Ox (C) Unconditional branch to any address LABEL in microcode memory: goto LABEL (d) Subroutine call support, where subroutine is stored at address LABEL: call subroutine LABEL retum (e) Support repeat instruction, for repeating a block of code COUNT times: repeat (COUNT) LABEL LABEL is the address of the last instruction in the loop. Exercise 10.9 Design a micro programmed state machine to support 4 deep nested loops and conditional jump instructions with the requirements given in (1) and (2), respectively. Draw an RTL diagram clearly specifying sizes of instruction register, multiplexers, comparators, micro PC register, and all other registers in your design. 1. The loop machine should support conditional loop instructions of the format: if (CONDI) repeat END LABEL COUNT The micro code checks COND i=0,1,2,3 and, if it is TRUE, the state machine repeats COUNT times a block of instructions starting from the next instruction to the instruction labeled with END LABEL. Assume the size of PM is 256 words and a 6 bit counter that stores the 450 Digital Design of Signal Processing Systems If (R4 0 ) jump R If (Re> 0 ) jump R Call subroutine Rs and return support Rito Rs are 8 bit registers. A branch address or subroutine address can be written in Rs using a load instruction. As given in the instruction set jump and subroutine instructions are developed to use the contents of Rs as address of the next instruction. The conditions are based on the content of R. Draw the RTL diagram of the datapath and micro programmed state machine. Show all the control signals. Specify the instruction format and size. The datapath should be optimal using only one carry propagate adder (CPA) by appropriately using a compression block to compress the number of operands to two. Exercise 10.8 Design a micro coded state machine based design, with the following features. 1. There are three register files, P, Q and R. Each register file has four 8 bit registers. 2. There is an adder and logic unit to perform addition, subtraction, AND, OR and XOR operations. 3. There is 264 deep micro code memory. 4. The state machine supports the following instructions: (a) Load constant into ith register of Por Q: P;=const Qi=const (b) Perform any arithmetic or logic operation given in (2) on operands in register files Pand Q, and store the result in register file R: R;=P; op Ox (C) Unconditional branch to any address LABEL in microcode memory: goto LABEL (d) Subroutine call support, where subroutine is stored at address LABEL: call subroutine LABEL retum (e) Support repeat instruction, for repeating a block of code COUNT times: repeat (COUNT) LABEL LABEL is the address of the last instruction in the loop. Exercise 10.9 Design a micro programmed state machine to support 4 deep nested loops and conditional jump instructions with the requirements given in (1) and (2), respectively. Draw an RTL diagram clearly specifying sizes of instruction register, multiplexers, comparators, micro PC register, and all other registers in your design. 1. The loop machine should support conditional loop instructions of the format: if (CONDI) repeat END LABEL COUNT The micro code checks COND i=0,1,2,3 and, if it is TRUE, the state machine repeats COUNT times a block of instructions starting from the next instruction to the instruction labeled with END LABEL. Assume the size of PM is 256 words and a 6 bit counter that stores the