URL https://opencores.org/ocsvn/dmt_tx/dmt_tx/trunk

Subversion Repositories dmt_tx

[/] [dmt_tx/] [trunk/] [myhdl/] [rtl/] [cmath.py] - Diff between revs 31 and 32

Rev 31	Rev 32
Line 97...	Line 97...
`This turns out to be:`	`This turns out to be:`

`y_re = a_re * b_re - a_im * b_im`	`y_re = a_re * b_re - a_im * b_im`
`y_im = a_re * b_im + a_im * b_re`	`y_im = a_re * b_im + a_im * b_re`

	`The output is expected to have at least the same width as the input.`
	`The products are scaled back to the input width and in case an extra`
	`bit would be needed due to the addition or subtraction, an overflow`
	`is signaled.`

	`At the moment the overflowing output is saturated to the respective`
	`limit, based on the input width. So a wider output width is not used`
	`with the current implementation.`

`I/O pins:`	`I/O pins:`
`=========`	`=========`
`a : input a`	`a : input a`
`b : input b`	`b : input b`
Line 115...	Line 123...
`# use input width of a_re, assume a_im, b_re and b_im are the same`	`# use input width of a_re, assume a_im, b_re and b_im are the same`
`width = len(a_re)`	`width = len(a_re)`

`# calculate min and max value range`	`# calculate min and max value range`
`smin = -2**(width-1)`	`smin = -2**(width-1)`
`smax = 2**(width-1)-1`	`smax = 2**(width-1)`

`#print 'cmult input width: ', width`	`#print 'cmult input width: ', width`

`prod_a = a_re * b_re`	`prod_a = a_re * b_re`
`prod_b = a_im * b_im`	`prod_b = a_im * b_im`