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The code declares an 8-bit reg called vect and initializes it to a value of 4. The list describes how the separate bits of that vector can be addressed. reg [7:0] vect; vect = 4; // fills vect with the pattern 00000100. // msb is bit 7, lsb is bit 0. — If the value of addr is 2, then vect[addr] returns 1.
This means that each bit can be one of 4 values: 0,1,x,z. With the "case equality" operator, ===, x's are compared, and the result is 1. With ==, the result of the comparison is not 0, as you stated; rather, the result is x, according to the IEEE Std (1800-2009), section 11.4.5 "Equality operators": For the logical equality and logical ...
Apr 11, 2013 · That's not a command, it's the width of the wire. For example here: wire [NumberOfBits-1:0] MuxOut; NumberOfBits is a parameter of value 4, so after substitution the wire width becomes [4-1:0], or [3:0]. This just means a wire of width 4, with individual bits of 3, 2, 1, and 0. answered Apr 11, 2013 at 6:35.
Jun 26, 2013 · This isn't quite correct. In Verilog, a vector (or any other) object is 'true' if it is non-zero, and it is known - in other words, it does not contain x/z metavalues. So, it's not 'tested for equality to 0'. @VL: try not to combine Verilog and SV questions - they're different languages. You wouldn't ask a C question in a C++ group, or vice-versa.
Feb 16, 2016 · 27. <= is a nonblocking assignment. It is used to describe sequential logic, like in your code example. Refer to IEEE Std 1800-2012, section 10.4.2 "Nonblocking procedural assignments". = is for blocking assignments. It is used to describe combinational logic. See also Nonblocking Assignments in Verilog Synthesis, Coding Styles That Kill!
Aug 22, 2018 · For example, in this code, when you're using a non-blocking assignment, its action won't be registered until the next clock cycle. This means that the order of the assignments is irrelevant and will produce the same result. The other assignment operator, '=', is referred to as a blocking assignment. When '=' assignment is used, for the purposes ...
Oct 10, 2013 · Three possible reason to have and keep the | for the provided code are: It gives guidance to the synthesizer: first OR the address bits then compare to 0, instead of comparing each address bit to 0 then ANDing the results. It is the same functional result with different gate configurations. It following a coding style or formatting style ...
reg[7:0] numbers[3:0] is a 1-D array with 4 elements, named numbers, each of which is an 8-bit register. An element of numbers is accessed as numbers[index] numbers[i][j] is a bit-select of numbers[i]. It accesses bit j in the i th element of numbers. As toolic says, it's more conventional for array indices to be numbered [lsb:msb], but there's ...
First IEEE appearance is IEEE 1364-2001 (Verilog) § 4.2.1 "Vector bit-select and part-select addressing". Here is an direct example from the LRM: The value to the left always the starting index. The number to the right is the width and must be a positive constant. the + and - indicates to select the bits of a higher or lower index value then ...
Oct 5, 2016 · The ^ symbol implements the XOR function. See here for a full list of Verilog operators. Earn 10 reputation (not counting the ) in order to answer this question. The reputation requirement helps protect this question from spam and non-answer activity.
