Lecture 18 Pico Blaze Instruction Set Assembler Directives

Lecture 18 Pico. Blaze Instruction Set & Assembler Directives ECE 448 – FPGA and ASIC Design with VHDL

Required reading • P. Chu, FPGA Prototyping by VHDL Examples Chapter 15 Pico. Blaze Assembly Code Develop Recommended reading • K. Chapman, Pico. Blaze for Spartan-6, Virtex-6, and 7 -Series (KCPSM 6) ECE 448 – FPGA and ASIC Design with VHDL 2

Pico. Blaze-6 Programming Model Bank A Bank B FFC FFD FFE FFF ECE 448 – FPGA and ASIC Design with VHDL 3

Syntax and Terminology Syntax Example s. X s 7 KK 0 x. AB PORT(KK) PORT(2) Definition Value at register 7 Constant AB (in hex) Input value from port 2 PORT((s. X)) PORT((sa)) Input value from the port specified RAM(KK) RAM(4) by register a Value from RAM location 4

Addressing modes Immediate mode SUB s 7, 0 x 07 ADDC s 2, 0 x 08 s 7 <= s 7 – 0 x 07 s 2 <= s 2 + 0 x 08 + C Direct mode ADD sa, sf IN s 5, 0 x 2 a Indirect mode STORE s 3, (sa) IN s 9, (s 2) sa <= sa + sf s 5 <= PORT(0 x 2 a) RAM((sa)) <= s 3 s 9 <= PORT((s 2))

Pico. Blaze Development Environments Platform support Xilinx KCPSM 3/6 Windows Command-line in DOS Assembler window Instruction Syntax KCPSM 3/6 Facilities provided for Instruction Set Simulator VHDL simulation Simulator Breakpoints N/A Register Viewer N/A Memory Viewer N/A FIDEx IDE Windows XP, Windows 7 and 8 Graphical FIDEx IDE Graphical/ Interactive Yes Yes

KCPSM 6 Assembler Files KCPSM 6. EXE ECE 448 – FPGA and ASIC Design with VHDL

Directives of Assembly Language Function Locating Code Aliasing Register Names Declaring Constants KCPSM 3/6 Directive FIDEx IDE Directive ADDRESS 3 FF ORG 0 x 3 FF NAMEREG s 5, myregname EQU s 5 CONSTANT myconstant, 80 myconstant EQU 0 x 80 Name using the same base Specify the VHDL template file in the Naming the program ROM filename as the assembler source project settings under processor tab file and compiler options sw_port EQU 0 x 01 ; 8 -bit switches sw_in EQU sf IN sw_in, sw_port ; read switch input Equating symbolic name N/A for an I/O port ID data EQU s 0 ; reg for tmp data led_port EQU 0 x 05 OUT data, led_port

Differences between Mnemonics of Instructions KCPSM 3/ 6 Mnemonic FIDEx IDE Mnemonic RETURN C RETURN NC RETURN Z RETURN NZ RETURNI ENABLE RETURNI DISABLE RETI DISABLE ENABLE INTERRUPT EINT DISABLE INTERRUPT DINT

Differences between Mnemonics of Instructions ADDCY s. X, s. Y ADDC s. X, s. Y SUBCY s. X, s. Y SUBC s. X, s. Y INPUT s. X, (s. Y) INPUT s. X, kk IN s. X, kk OUTPUT s. X, (s. Y) OUT s. X, (s. Y) COMPARE s. X, s. Y COMP s. X, s. Y

Differences between Programs A 5 0 x. A 5

Basic Data Movement Instructions

Data Movement Instructions CZ IMM, DIR LOAD s. X, s. Y s. X <= s. Y LOAD s. X, KK s. X <= KK -

Logic Instructions & Bit Manipulation

Logic instructions 1. AND s. X, s. Y s. X <= s. X and s. Y AND s. X, KK s. X <= s. X and KK 2. OR OR s. X, s. Y s. X <= s. X or s. Y OR s. X, KK s. X <= s. X or KK 3. XOR s. X, s. Y s. X <= s. X xor s. Y XOR s. X, KK s. X <= s. X xor KK CZ IMM, DIR 0

Questions Perform the following operations in the assembly language of Pico. Blaze 1. Set the most significant bit of the register s 0 to 1 1. Clear two middle bits of the register s 1 1. Toggle the least significant bit of the register s 2

Answers 1. Set the most significant bit of the register s 0 to 1 BIT 7 EQU 0 x 80 OR s 0, BIT 7 2. Clear two middle bits of the register s 1 BITS 43 C EQU 0 x. E 7 AND s 1, BITS 43 C 3. Toggle the least significant bit of the register s 2 BIT 0 EQU 0 x 01 XOR s 2, BIT 0

Arithmetic Instructions & Multiple-Byte Manipulation

Arithmetic Instructions (1) CZ Addition IMM, DIR ADD s. X, s. Y s. X <= s. X + s. Y ADD s. X, KK s. X <= s. X + KK ADDC s. X, s. Y s. X <= s. X + s. Y + CARRY ADDC s. X, KK s. X <= s. X + KK + CARRY

Questions Perform the following operation in the assembly language of Pico. Blaze Add two 3 -byte numbers X=(x 2, x 1, x 0) and Y=(y 2, y 1, y 0), stored originally in registers (s 2, s 1, s 0) and (s 5, s 4, s 3), accordingly.

Answer x 0 x 1 x 2 y 0 y 1 y 2 EQU EQU EQU s 0 s 1 s 2 s 3 s 4 s 5 ADD x 0, y 0 ADDC x 1, y 1 ADDC x 2, y 2

Arithmetic Instructions (2) CZ Subtraction SUB s. X, s. Y s. X <= s. X – s. Y SUB s. X, KK s. X <= s. X – KK SUBC s. X, s. Y s. X <= s. X – s. Y – CARRY SUBC s. X, KK s. X <= s. X – KK – CARRY IMM, DIR

Questions Perform the following operation in the assembly language of Pico. Blaze Perform the subtraction X=X-Y, where X=(x 2, x 1, x 0) and Y=(y 2, y 1, y 0), and these variables are originally stored in registers (s 2, s 1, s 0) and (s 5, s 4, s 3), accordingly.

Answer x 0 x 1 x 2 y 0 y 1 y 2 EQU EQU EQU s 0 s 1 s 2 s 3 s 4 s 5 SUB x 0, y 0 SUBC x 1, y 1 SUBC x 2, y 2

Shifts & Rotations

Edit instructions - Shifts *All shift instructions affect Zero and Carry flags

Edit instructions - Rotations *All rotate instructions affect Zero and Carry flags

Questions Perform the following operation in the assembly language of Pico. Blaze Perform the left shift (C, X) <= X << 1, where X = (x 2, x 1, x 0) is stored in registers (s 2, s 1, s 0), and the most significant bit of X is shifted into the carry flag.

Answer x 0 x 1 x 2 EQU s 0 EQU s 1 EQU s 2 SL 0 SLA x 0 x 1 x 2

Test, Compare, and Program Flow Instructions

Test and Compare Instructions CZ TEST IMM, DIR TEST s. X, s. Y C = odd parity of s. X and s. Y => none TEST s. X, KK the result s. X and KK => none COMPARE COMP s. X, s. Y s. X – s. Y => none COMP s. X, KK s. X – KK => none IMM, DIR

Program Flow Control Instructions (1) JUMP AAA PC <= AAA JUMP C, AAA if C=1 then PC <= AAA else PC <= PC + 1 JUMP NC, AAA if C=0 then PC <= AAA else PC <= PC + 1 JUMP Z, AAA if Z=1 then PC <= AAA else PC <= PC + 1 JUMP NZ, AAA if Z=0 then PC <= AAA else PC <= PC + 1

If-else statement C if (s 0 == s 1) { ………. } else { ………. . } Assembly language

If-else statement C Assembly language if (s 0 == s 1) { ………. } else { ………. . } COMP s 0, s 1 JUMP NZ, else_branch ………. . JUMP if_done else_branch: ………. . if_done:

Switch statement C switch (s 0) { case value_1: ………. break; case value_2: ………. break; case value_3: ………. break; default: ………. break; } Assembly language

Switch statement C switch (s 0) { case value_1: ………. break; case value_2: ………. break; case value_3: ………. break; default: ………. break; } Assembly language COMP s 0, value_1 JUMP NZ, case_2 ………. JUMP case_done case_2: COMP s 0, value_2 JUMP NZ, case_3 ………. JUMP case_done case_3: COMP s 0, value_3 JUMP NZ, default ………. JUMP case_done default: ………. case_done:

For loop C for(i=MAX, i>=0, i--) { …………… } Assembly language

For loop C for(i=MAX; i>0; i--) { …………… } for(i=MAX; i>=0; i--) { …………… } Assembly language LOAD s 0, MAX for_loop: ………. SUB s 0, 1 JUMP NZ, for_loop LOAD s 0, MAX for_loop: ………. SUB s 0, 1 JUMP NC, for_loop

Subroutines

Subroutine-Related Instructions CALL AAA TOS <= TOS+1; STACK[TOS] <= PC; PC <= AAA CALL C | Z , AAA if C | Z =1 then TOS <= TOS+1; STACK[TOS] <= PC; PC <= AAA else PC <= PC + 1 CALL NC | NZ , AAA if C | Z =0 then TOS <= TOS+1; STACK[TOS] <= PC; PC <= AAA else PC <= PC + 1

Subroutine-Related Instructions RET PC <= STACK[TOS] + 1; TOS <= TOS - 1 RET C|Z if C | Z =1 then PC <= STACK[TOS] + 1; TOS <= TOS - 1 else PC <= PC + 1 RET NC | NZ if C | Z =0 then PC <= STACK[TOS] + 1; TOS <= TOS - 1 else PC <= PC + 1

Subroutine Call Flow

Instructions Involving Data Memory

Data Movement Instructions Involving Data Memory CZ DIR, IND STORE s. X, KK RAM(KK) <= s. X - STORE s. X, s. Y RAM((s. Y)) <= s. X DIR, IND FETCH s. X, KK s. X <= RAM(KK) FETCH s. X, (s. Y) s. X <= RAM((s. Y) -

Example 1: Clear Data RAM of the size of 64 bytes ; ============================= ; routine: clr_data_mem ; function: clear data ram ; temp register: data, s 2 ; ============================= RAM_SIZE EQU 0 x 40 ; size of RAM = 64 clr_data_mem: load s 2, RAM_SIZE ; unitize loop index to 64 load s 0, 0 x 00 clr_mem_loop: sub s 2, 0 x 01 ; dec loop index store s 0, (s 2) jump nz, clr_mem_loop ret ; repeat until s 2=0

Input/Output Instructions

Input/Output Instructions DIR, IND IN IN s. X, KK s. X <= PORT(KK) CZ - IN s. X, (s. Y) s. X <= PORT((s. Y)) DIR, IND OUT s. X, KK PORT(KK) <= s. X OUT s. X, (s. Y) PORT((s. Y)) <= s. X -

Example 2: Clear External RAM of the size of 64 bytes ; ============================= ; routine: clr_ext_mem ; function: clear data ram ; temp register: data, s 2 ; ============================= RAM_SIZE EQU 0 x 40 ; size of RAM = 64 clr_ext_mem: load s 2, RAM_SIZE ; unitize loop index to 64 load s 0, 0 x 00 clr_mem_loop: sub s 2, 0 x 01 ; dec loop index out s 0, (s 2) jump nz, clr_mem_loop return ; repeat until s 2=0