CSE 378
Fall 2002
Computer Hardware Design
R. E. Haskell
Lab 9 – The WC16 Core – Multiplication and Division – DIO2 Board
The WC16 Core
A final version of the WC16 core is shown in Figure 1. Note that it includes a new
Funit, called Funit2, which includes the multiplication and division primitives, mpp and shldc,
shown in Table 1.
Table 2 is a list of new I/O instructions and Table 3 is a list of additional transfer and
multi-cycle instructions. These instructions are included in the package opcodes.vhd used in
Labs 7 and 8.
The top-level design for Lab 9 is shown in Figure 2.
Table 1 New Funit Instructions
Code
001D
001E
Name
mpp
shldc
Function
multiply partial product (used for multiplication)
shift left and decrement conditionally (used for division)
Table 2 New I/O Instructions
Code
0034
003A
Name
@
DIO2@
Function
“Fetch” Push contents of RAM address, T, into T via E1.
“DIO2 fetch” Push 8-bit value to DIO2 data bus into T via E1.
Table 3 New Transfer and Multi-Cycle Instructions
Code
0106
0107
0108
0109
010A
010B
010C
010D
010E
010F
0110
Name
JB1LO
JB2LO
JB3LO
JB4LO
JB1HI
JB2HI
JB3HI
JB4HI
!
DIO2!
LCDinst!
0111
LCDdata!
Function
Jump if input pin B1 is LO
Jump if input pin B2 is LO
Jump if input pin B3 is LO
Jump if input pin B4 is LO
Jump if input pin B1 is HI
Jump if input pin B1 is HI
Jump if input pin B1 is HI
Jump if input pin B1 is HI
“Store” Write the word in N at the address in T. Pop both T and N.
Write the byte in N at the DIO2 address in T. Pop both T and N.
Write the instruction byte in N at the DIO2 dummy address (0) in T.
Pop both T and N.
Write the data byte in N at the DIO2 dummy address (0) in T. Pop
both T and N.
1
M
R
0
psel
P1
T
0
Pmux 1
rinsel
Rmux 1
Rin
Pin
P(15:0)
pload
pinc
clr
clk
PC
plus1
P
rsel
rload
rdec
ReturnStack
clr
clk
rpush
rpop
E1(15:0)
S(1:8)
R
M(15:0)
M
y
M
irload
0
1
E2(15:0)
S
2
E1 E2 N2
3
4
Tmux
clr
clk
IR
5
6
N
7
tsel(2:0)
Tin
tload
icode
R
B(1:4)
T
clr
clk
nload
nsel
ssel
clr
clk
dpush
dpop
DataStack
oe
we
WC16_control
N2
cs
N
T
T(15:0)
digload
N(15:0)
LCD_RW
Funit2
LCD_RS
LCD_E
y1(15:0)
The WC16
WHYP Core
Fig. 1 The WC16 WHYP Core
2
Fcode(5:0)
y(15:0)
bn
mclk
IBUFG
clkdiv
Lab9
clr
led
P
cclk
clk
clk
clr
P
T
T
Program
ROM
clr
M
DigDisplay
M
WC16
cclk
digload
oe
we
cs
LCD_RW
LCD_RS
LCD_E
B
S
BTN4
SW(1:8)
‘1’
LD(1:8)
Fig. 2 Lab 9 Top-level Design
3
ldg
A(1:4)
AtoG(6:0)
digload
Multiplication and Division
Multiplication of a 16-bit unsigned number in T by a 16-bit unsigned number in N
producing a 32-bit product in T:N can be accomplished by adding the variables shown in Figure
3 to the process in Funit2 and by implementing the Funit2 operation mpp as shown in Figure 4.
variable
variable
variable
variable
variable
AVector:
BVector:
CVector:
yVector:
y1_tmp:
STD_LOGIC_VECTOR
STD_LOGIC_VECTOR
STD_LOGIC_VECTOR
STD_LOGIC_VECTOR
STD_LOGIC_VECTOR
(width downto 0);
(width downto 0);
(width downto 0);
(width downto 0);
(width-1 downto 0);
Fig. 3 Variables to add to process in Funit2
when "011101" =>
-- mpp
if b(0) = '1' then
yVector := AVector + CVector;
else
yVector := AVector;
end if;
y <= yVector(width downto 1);
y1 <= yVector(0) & b(width-1 downto 1);
when "011110" =>
-- shldc
yVector := a & b(width-1);
y1_tmp := b(width-2 downto 0) & '0';
if yVector >= CVector then
yVector := yVector - CVector;
y1_tmp(0) := '1';
end if;
y <= yVector(width-1 downto 0);
y1 <= y1_tmp;
Fig. 4 Implementation of mpp and shldc in Funit2
The WHYP word UM* ( u1 u2 - upL upH ) can then be implemented using the colon definition
shown in Figure 5. Note that this multiplication will take 23 clock cycles to execute, including
the CALL and RET instructions (2 clock cycles each).
: UM*
( u1 u2 - upL upH )
0
mpp mpp mpp mpp
mpp mpp mpp mpp
mpp mpp mpp mpp
mpp mpp mpp mpp
ROT_DROP ;
Fig. 5 The WHYP multiplication word, UM*
4
Dividing a 32-bit unsigned number in N2:N by a 16-bit unsigned number in T producing a
16-bit quotient in T and a 16-bit remainder in N can be accomplished by adding the variables
shown in Figure 3 to the process in Funit2 and by implementing the Funit2 operation shldc as
shown in Figure 4.
The WHYP word UM/MOD ( unL unH ud -- ur uq ) can then be implemented using the
colon definition shown in Figure 6. Note that this division will take 22 clock cycles to execute,
including the CALL and RET instructions.
: UM/MOD ( unL unH ud -- ur uq )
-ROT
shldc shldc shldc shldc
shldc shldc shldc shldc
shldc shldc shldc shldc
shldc shldc shldc shldc
ROT_DROP_SWAP ;
Fig. 5 The WHYP division word, UM/MOD
DIO2 Board
The DIO2 board that is connected to the Digilab2 board contains 15 pushbutton switches,
16 LEDs, 8 switches, four 7-segment displays, and a Liquid Crystal Display (LDC). All the I/O
devices except the LCD are controlled through a Xilinx CPLD that is on the DIO2 board. The
operation of this DIO2 board is described in the DIO2 Reference Manual, available online from
www.digilentinc.com.
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Lab 9
1. Modify the function unit, Funit1, used in Lab 8 to include the new operations, mpp
and shldc. Call the new function unit Funit2. Note that this function unit has three
input busses and two output busses.
2. Write a structural VHDL program for the module WC16 shown in Figure 1. Write
the VHDL program for the controller WC16_control (modify WC16C_control.vhd
from Lab 8). In addition to all of the instructions from Lab 8, implement the new
instructions in Table 1.
3. Write a structural VHDL program for the top-level design Lab9 shown in Figure 2.
4. Test your Lab9 module by compiling each of the following WHYP programs
(available on the web) using the program WC16.EXE (available on the web) that
will produce the VHDL code to insert in your ROM program and then download the
program to the Spartan II board. Demonstrate each program to your lab instructor
as you get it to work.
sdigtest.whp
hex2asc.whp
minmax.whp
mul.whp
div.whp
fact16.whp
leap.whp
--------
tests the switches and 7-segment displays
converts hex to ascii
finds the min and max of two numbers
multiplies two 16-bit numbers
divides a 32-bit number by a 16-bit number
computes the factorial of a number
checks if a year is a leap year
Extra credit:
Implement one or more of the instructions in Tables 2 and 3 that relate to the DIO2 board.
Run one or more of the .whp programs in Part 4 above where the input and/or output use the
DIO2 board.
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