第六章VHDL设计应用实例 6.18位加法器的设计 1、设计思路 多位加法器的构成方式:并行进位 串行进位 并行进位:速度快、占用资源多 串行进位:速度慢、占用资源少
1 第六章 VHDL设计应用实例 6.1 8位加法器的设计 1、设计思路 多位加法器的构成方式：并行进位 串行进位 并行进位：速度快、占用资源多 串行进位：速度慢、占用资源少
速度与资源的折中选择:并行加法器与串行级联 49MAX+plus II-h: \eda_tech_app\e6_1 \adder8b- [adder8b gdf -Graphic Editor] □x MAX+plus II File Edit view Symbol Assign Utilities Options Window Help × 口圖当回回△國囫郾感國為囡烈d ADDER4B s【3..。 R【3.,。 b.01 aa[.0 ADDER4B s|7.4 B【3
2 速度与资源的折中选择：并行加法器与串行级联
2、4位并行加法器 49 MAX+plus lI-f: \dh\mp2 \eda_tech_app\e6_1 \adder 4b-[adder 4b. vhd-Text Editor ×」 FN MAX+plus ll Eile Edit Templates Assign lties Options window Hep library ieee use ieee std logic 1164.alli use ieee std logic unsigned alli entity adder4b is rt(cin: in std log std logic vector(3 downto 0) s: out std logic vector(3 downto 0)i t: out std logic) end adder4bi architecture art of adder4b is signal sint: std logic vector(4 downto 0)i signal aa, bb: std logic vector(4 downto 0 egin a<=0&a; bb<=io &b sint<=aa+bb+cin s<=sint (3 downto o cout<=sint (4 Line 11 Col 42 4
3 2、4位并行加法器
3、8位二进制加法器 C,aMAX+plus II-f:\dh\mp2\eda tech app \e6 1\ad EE MAX+pus II Ele Edit Templates assign Utilties options window Help 口哆舀叫△國囫郾郾四囚為圖面剧烈雷 Courier New20-B library ieee use ieee std logic 1164.alli use ieee std logic unsigned. all entity adders is port (cin: in std logici a, b:in std logic vector(7 downto O s: out std logic vector(7 downto 0) cout: out sta logic)i end adders; architecture art of adder8b is component adder4b port(cin: in std logici a b:in std logic vector(3 downto 0)i s: out std logic vector(3 downto 0); cout: out std logic end component signal carry out: std logic; Line 1 Col 1INS 4
4 3、8位二进制加法器
2MAX+plus lI-f:\(dh mp2\(eda_tech_app e6_1\adder4b-[adderBb, whd-Text Editor] 回×」 8 MAX+plus Il Eile Edit Templates Assign Utilties Options Window Hep 口圖舀属回△國囫国感国国為画A武雷 Courier New. B涅 begi ul: adder port map(cin=>cin, a=>a(3 downto 0) b=>b(3 downto 0) s(3 downto 0) cout=>carry out)i u2: adder4b port map(cin=>carry out >a(7 downto 4) b=>b(7 downto 4) s=>s(7 downto 4) cout=>cout)i end art LLine31col16Ns←
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