按机器补码浮点运算步骤,计算[x±y]补.
(1)x=2-011× 0.101 100,y=2-010×(-0.011 100);
(2)x=2-011×(-0.100 010),y=2-010×(-0.011 111);
(3)x=2101×(-0.100 101),y=2100×(-0.001 111)。
先将x、y转换成机器数形式:
(1)x=2-011× 0.101 100,y=2-010×(-0.011 100)
[x]补=1,101;0.101 100, [y]补=1,110;1.100 100
[Ex]补=1,101, [y]补=1,110, [Mx]补=0.101 100, [My]补=1.100 100
1)对阶:
[DE]补=[Ex]补+[-Ey]补 = 11,101+ 00,010=11,111 < 0,
应Ex向Ey对齐,则:[Ex]补+1=11,101+00,001=11,110 = [Ey]补
[x]补=1,110;0.010 110
2)尾数运算:
[Mx]补+[My]补= 0.010 110 + 11.100 100=11.111010
[Mx]补+[-My]补=0.010 110 + 00.011100= 00.110 010
3)结果规格化:
[x+y]补=11,110;11.111 010 = 11,011;11.010 000 (尾数左规3次,阶码减3)
[x-y]补=11,110;00.110 010, 已是规格化数。
4)舍入:无
5)溢出:无
则:x+y=2-101×(-0.110 000)
x-y =2-010×0.110 010
(2)x=2-011×(-0.100010),y=2-010×(-0.011111)
[x]补=1,101;1.011 110, [y]补=1,110;1.100 001
1) 对阶:过程同(1)的1),则
[x]补=1,110;1.101 111
[Mx]补+[My]补= 11.101111 + 11. 100001 = 11.010000
[Mx]补+[-My]补= 11.101111 + 00.011111 = 00.001110
[x+y]补=11,110;11.010 000,已是规格化数
[x-y]补=11,110;00.001 110 =11,100;00.111000 (尾数左规2次,阶码减2)
则:x+y=2-010×(-0.110 000)
x-y =2-100×0.111 000
(3)x=2101×(-0.100 101),y=2100×(-0.001 111)
[x]补=0,101;1.011 011, [y]补=0,100;1.110 001
[DE]补=00,101+11,100=00,001 >0,应Ey向Ex对齐,则:
[Ey]补+1=00,100+00,001=00,101=[Ex]补
[y]补=0,101;1.111 000(1)
[Mx]补+[My]补= 11.011011+ 11.111000(1)= 11.010011(1)
[Mx]补+[-My]补= 11.011011+ 00.000111(1)= 11.100010(1)
[x+y]补=00,101;11.010 011(1),已是规格化数
[x-y]补=00,101;11.100 010(1)=00,100;11.000 101 (尾数左规1次,阶码减1)
4)舍入:
[x+y]补=00,101;11.010 011(舍)
[x-y]补 不变
则:x+y=2101×(-0.101 101)
x-y =2100×(-0.111 011)
这道题你会答吗?花几分钟告诉大家答案吧!
扫描二维码,关注牛客网
下载牛客APP,随时随地刷题
先将x、y转换成机器数形式:
(1)x=2-011× 0.101 100,y=2-010×(-0.011 100)
[x]补=1,101;0.101 100, [y]补=1,110;1.100 100
[Ex]补=1,101, [y]补=1,110, [Mx]补=0.101 100, [My]补=1.100 100
1)对阶:
[DE]补=[Ex]补+[-Ey]补 = 11,101+ 00,010=11,111 < 0,
应Ex向Ey对齐,则:[Ex]补+1=11,101+00,001=11,110 = [Ey]补
[x]补=1,110;0.010 110
2)尾数运算:
[Mx]补+[My]补= 0.010 110 + 11.100 100=11.111010
[Mx]补+[-My]补=0.010 110 + 00.011100= 00.110 010
3)结果规格化:
[x+y]补=11,110;11.111 010 = 11,011;11.010 000 (尾数左规3次,阶码减3)
[x-y]补=11,110;00.110 010, 已是规格化数。
4)舍入:无
5)溢出:无
则:x+y=2-101×(-0.110 000)
x-y =2-010×0.110 010
(2)x=2-011×(-0.100010),y=2-010×(-0.011111)
[x]补=1,101;1.011 110, [y]补=1,110;1.100 001
1) 对阶:过程同(1)的1),则
[x]补=1,110;1.101 111
2)尾数运算:
[Mx]补+[My]补= 11.101111 + 11. 100001 = 11.010000
[Mx]补+[-My]补= 11.101111 + 00.011111 = 00.001110
3)结果规格化:
[x+y]补=11,110;11.010 000,已是规格化数
[x-y]补=11,110;00.001 110 =11,100;00.111000 (尾数左规2次,阶码减2)
4)舍入:无
5)溢出:无
则:x+y=2-010×(-0.110 000)
x-y =2-100×0.111 000
(3)x=2101×(-0.100 101),y=2100×(-0.001 111)
[x]补=0,101;1.011 011, [y]补=0,100;1.110 001
1)对阶:
[DE]补=00,101+11,100=00,001 >0,应Ey向Ex对齐,则:
[Ey]补+1=00,100+00,001=00,101=[Ex]补
[y]补=0,101;1.111 000(1)
2)尾数运算:
[Mx]补+[My]补= 11.011011+ 11.111000(1)= 11.010011(1)
[Mx]补+[-My]补= 11.011011+ 00.000111(1)= 11.100010(1)
3)结果规格化:
[x+y]补=00,101;11.010 011(1),已是规格化数
[x-y]补=00,101;11.100 010(1)=00,100;11.000 101 (尾数左规1次,阶码减1)
4)舍入:
[x+y]补=00,101;11.010 011(舍)
[x-y]补 不变
5)溢出:无
则:x+y=2101×(-0.101 101)
x-y =2100×(-0.111 011)