pragma SDS data buffer_depth
Description
This pragma must be specified immediately preceding a function declaration, or
immediately preceding another #pragma SDS bound to the function
declaration, and applies to all the callers of the function.
This pragma only applies to arrays that map to BRAM or FIFO interfaces. For a
BRAM-mapped array, the <BufferDepth> value specifies hardware
multi-buffer depth. For a FIFO-mapped array, the <BufferDepth>
value specifies the depth of the hardware FIFO allocated for the array. For this
pragma, the following must be true:
- BRAM: 1 ≤ <BufferDepth> ≤ 4, and 2 ≤ ArraySize ≤ 16384.
- FIFO: <BufferDepth> = 2n, where 4 ≤ n ≤ 20.
TIP: When the pragma is not specified, the default
BUFFER_DEPTH is 1.Syntax
The syntax of this pragma is:
#pragma SDS data buffer_depth(ArrayName:<BufferDepth>)Where:
ArrayName: Specifies one of the formal parameters of the function to assign the pragma to.- <BufferDepth> must a compile-time constant value.
- Multiple arrays can be specified as a comma separated list in one pragma.
For example:
#pragma SDS data buffer_depth(ArrayName1:BufferDepth1, ArrayName2:BufferDepth2)
Example 1
This example specifies a multi-buffer of size 4 used for the RAM interface of
argument a:
#pragma SDS data buffer_depth(a:4)
void foo(int a[1024], b[1024);