新的一天开始，重复的一天也开始了。
还不知道
–===========================================================================
— RESIZE Functions
–===========================================================================
— Id: R.1
— function RESIZE (ARG: SIGNED; NEW_SIZE: NATURAL) return SIGNED;
— Result subtype: SIGNED(NEW_SIZE-1 downto 0)
— Result: Resizes the SIGNED vector ARG to the specified size.
— To create a larger vector, the new [leftmost] bit positions
— are filled with the sign bit (ARG’LEFT). When truncating,
— the sign bit is retained along with the rightmost part.
— Id: R.2
–function RESIZE (ARG: UNSIGNED; NEW_SIZE: NATURAL) return UNSIGNED;
— Result subtype: UNSIGNED(NEW_SIZE-1 downto 0)
— Result: Resizes the SIGNED vector ARG to the specified size.
— To create a larger vector, the new [leftmost] bit positions
— are filled with ‘0’. When truncating, the leftmost bits
— are dropped.
怎么来理解！
依然搞不明白
add_cast <= resize( product1, 40);
add_cast_1 <= resize( product2, 40);
add_temp <= resize(add_cast, 41) + resize(add_cast_1, 41);
sum1 <= (39 => ‘0’, OTHERS => ‘1’) WHEN add_temp(40) = ‘0’ AND add_temp(39) /= ‘0’
ELSE (39 => ‘1’, OTHERS => ‘0’) WHEN add_temp(40) = ‘1’ AND add_temp(39) /= ‘1’
ELSE (add_temp(39 DOWNTO 0));
的具体是怎么实现~~~~~~~~~~~~~~