;read in resultlengthXinpixelstextbox

invoke GetDlgItemTextA, [hwnd], resultlengthxpixelstextbox, bufferbuffer1, 100
cinvoke sscanf, bufferbuffer1, "%f", buffer1 

;read in MeasuredlengthXinpixelstextbox

invoke GetDlgItemTextA, [hwnd], measuredlengthxpixelstextbox, bufferbuffer1, 100
cinvoke sscanf, bufferbuffer1, "%f", buffer2

;resultlengthXpixels / MeasuredlengthXpixels

finit
fld dword [buffer1]
fld dword [buffer2] 
fdivp
fstp qword [buffer3]  

cinvoke sprintf, addr buffer1, "%.5lf", dword [buffer3], dword [buffer3 + 4]
invoke SetDlgItemTextA,[hwnd],resultlengthxtextbox,addr buffer1

.data
  bufferbuffer1 dd ?
  buffer1 dd ?
  buffer2 dd ?
  buffer3 dq ?  
    

;in data section do
float1 dq 222.34
float2 dq 233.38
bufferfloat dd ?

;in idata do
library msvcrt,"msvcrt.dll"


import msvcrt,\
         sprintf,"sprintf"
         

;then to add

fld float1     ; Push float1 value to ST(0)
fadd float2    ; Add float2 to ST(0)
fstp float1    ; Pop value from ST(0) to float1

;subtract

fld float1     ; Push float1 value to ST(0)
fsub float2    ; Subtract float2 to ST(0)
fstp float1    ; Pop value from ST(0) to float1

;multiply

fld float1     ; Push float1 value to ST(0)
fmul float2    ; Subtract float2 to ST(0)
fstp float1    ; Pop value from ST(0) to float1

;divide

fld float1     ; Push float1 value to ST(0)
fdiv float2    ; Subtract float2 to ST(0)
fstp float1    ; Pop value from ST(0) to float1

;then to get a readable answer do this
cinvoke sprintf, bufferfloat, "%.5lf", dword [float1], dword [float1 + 4]
invoke  MessageBoxA,[hwnd],bufferfloat,title,MB_OK

;if you need to read the floats from a textbox to the float1 and 22(string to float) do this

invoke GetDlgItemTextA, [hwnd], resultlengthxpixelstextbox, bufferbuffer1, 100
cinvoke sscanf, bufferbuffer1, "%f", float1

;then in idata add sscanf