汇编中FILD,FADD,FLD,FMUL都是有什么用?

[RexGene]

麻烦详细说说它们的详细计算过程

[BAYNPU]

浮点数运算指令：
fild:m16i/m32i/m64i;取存储器的整数,压入栈顶ST(0)。

FLD:M32R/M64R/M80R/ST(I);取存储器或ST(I)中的浮点数,压入栈顶。

FADD:M32R/M64R;ST(0)--ST(0)+32R/M64R。
FADD:ST,ST(I);ST(0)--ST(0)+ST(0)。
FADD:ST(I),ST(0);ST(I)--ST(I)+ST(0)。
FADD:ST(1)--ST(1)+ST(0),并出栈。

FMUL：M32R/M64R;ST(0)--ST(0)*M32R/M64R。
FMUL:ST,ST(I);ST(0)--ST(0)*ST(I)。
FMUL:ST(I),ST--(0);ST(I)*ST(0)。
FMUL;ST(1)--ST(1)*ST(0),并出栈。

[大熊猫侯佩]

参考一下浮点指令手册吧，eg:

FMUL

Title: Multiply

Syntax: FMUL [dest,src]
FMULP dest,ST
FMUL src
FIMUL src

Description:

Multiplies the source by the destination and returns the product in the destination. If two register operands are specified, one must be ST. If a memory operand is specified, the product replaces the value in ST. Memory operands can be 32- or 64-bit real numbers or 16- or 32-bit integers.

If no operand is specified, ST(1) is multiplied by ST and the stack is popped; the product is returned in ST. For FMULP, the source must be ST; the product is returned in the destination register and ST is popped.

-o-

----------------------------------------------------------------
FMUL [reg,reg] | fmul st,st(2) | 486 16
| fmul st(5),st |
| fmul |
----------------------------------------------------------------
FMULP reg,ST | fmulp st(6),st | 486 16
----------------------------------------------------------------
FMUL memreal | fmul DWORD PTR [bx] | 486 s=11,l=14

| fmul shortreal[di+3] |
| fmul longreal |
| |
----------------------------------------------------------------
FIMUL memint | fimul int16 | 486 w=23-27,d=22-24
| fimul warray[di] |
| fimul double |
| |
----------------------------------------------------------------
* The clocks in parentheses show times for short values--those with 40

trailing zeros in their fraction because they were loaded from a
short-real memory operand.

?The clocks in parentheses show typical speeds.

_ If the register operand is a short value--having 40 trailing zeros
in its fraction because it was loaded from a short-real memory
operand--then the timing is (112-126)+EA on the 8087 or 112-126 on
the 80287.
-o-

[cnzdgs]

F开头的基本上都是浮点指令，网上搜索一下可以找到详细的浮点指令集说明。

[大熊猫侯佩]

you can find them at Floating Point Help (at masm32\help\fphelp.hlp),

or HLA book

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浮点数

[dongyi940333]

前面的都说完，俺混点分^_^

[yayafu]

也给我点分吧

[hcgcoo1]

汇编中的这些浮点指令,我对它们的作用也懂点,但它们对浮点寄存器栈的影响我就不是十分清楚了.
希望高手在此点拨一下.
如,fmul指令,它就是将浮点寄存器栈中的最上面的两个数相乘,最后又将结果压入栈中.它对浮点寄存器的影响可以是这样吗:执行fmul,有两次出栈(即从栈中弹出两个操作数到浮点运算器中),得出结果后,又有一次入栈(保存结果到栈中)?

[gurongyong]

这些浮点指令

[sun32732]

ding............

[refgd]

看看怎么回事

[bksybq]

正在学习，刚遇到不懂，一搜就到这里了……呵呵

[xyers]

google到这里。留言。

[50米]

mark