Вычисление значения выражения a = b*(c-d) - c/(d-1) (RadASM, MASM)

include /masm32/include/masm32rt.inc
.data
a sword ?
b sword ?
cv sword ?
d sword ?
buf db 10 dup (?)
vb db "Enter a variable B: ",0
vc db "Enter a variable C: ",0
vd db "Enter a variable D (ATTENTION should not D = 1): ",0
rs db "B*(C-D)-C/(D-1) = ",0
em db 13,10,"press any key to exit...",0
.code
start:
invoke StdOut, addr vb
invoke StdIn, addr buf, LengthOf buf
invoke StripLF, addr buf
invoke atol,addr buf
mov dword ptr b,eax
invoke StdOut, addr vc
Invoke StdIn, addr buf, LengthOf buf
invoke StripLF, addr buf
invoke atol, addr buf
mov dword ptr cv,eax
invoke StdOut, addr vd
invoke StdIn, addr buf , LengthOf buf
invoke StripLF, addr buf
invoke atol, addr buf
mov dword ptr d,eax
mov ax,cv
sub ax,d;c-d
mov bx,b
mul bx;b*(c-d)
mov a,ax;a=b*(c-d)
mov bx,d
dec bx;d-1
mov ax,cv
div bx;c/d-a
sub a,ax;b*(c-d)-c/(d-1)
invoke dwtoa ,a,addr buf
invoke StdOut, addr rs
invoke StdOut, addr buf  
invoke StdOut, addr em
invoke StdIn, addr buf, LengthOf buf
invoke ExitProcess,0
end start

.486                ; create 32 bit code
.model  flat, stdcall       ; 32 bit memory model
option  casemap :none       ; case sensitive
include \masm32\include\windows.inc
include \masm32\include\masm32.inc
include \masm32\include\msvcrt.inc
include \masm32\macros\macros.asm
includelib \masm32\lib\msvcrt.lib
    .data
a   dd  ?
b   dd  ?
c_  dd  ?
d   dd  ?
vb  db  "Enter a variable B: ",0
vc  db  "Enter a variable C: ",0
vd  db  "Enter a variable D (ATTENTION should not D = 1): ",0
rs  db  "B*(C-D)-C/(D-1) = %d"
    db  13,10,"press any key to exit...",0
tpi db  "%d",0
tps db  "%s",0
.code
start:
    invoke  crt_printf, addr tps, addr vb
    invoke  crt_scanf, addr tpi, addr b
    invoke  crt_printf, addr tps, addr vc
    invoke  crt_scanf, addr tpi, addr c_
    invoke  crt_printf, addr tps, addr vd
    invoke  crt_scanf, addr tpi, addr d
    mov eax, [c_]
    sub eax, [d]        ;c-d
    imul    eax, [b]        ;b*(c-d)
    mov [a], eax        ;a=b*(c-d)
    dec [d]         ;d-1
    mov eax, [c_]
    cdq
    idiv    [d]         ;c/d-a
    sub [a],eax         ;b*(c-d)-c/(d-1)
    invoke  crt_printf, addr rs, [a]
    invoke  crt__getch
    invoke  crt_exit,0
    end start

.486                ; create 32 bit code
.model  flat, stdcall       ; 32 bit memory model
option  casemap :none       ; case sensitive
include \masm32\include\windows.inc
include \masm32\include\masm32.inc
include \masm32\include\msvcrt.inc
include \masm32\macros\macros.asm
includelib \masm32\lib\msvcrt.lib
    .data
a   dd  ?
b   dd  ?
c_  dd  ?
d   dd  ?
entr    db  "Enter a variable B",0
entrv   =   $ - 2
tp2 db  "%s (ATTENTION should not D = 1): ",0
rs  db  "B*(C-D)-C/(D-1) = %d"
    db  13,10,"press any key to exit...",0
tp1 db  '%s: ', 0
tpi db  "%d", 0
.code
start:
    invoke  crt_printf, addr tp1, addr entr
    invoke  crt_scanf, addr tpi, addr b
    inc byte ptr [entrv]
    invoke  crt_printf, addr tp1, addr entr
    invoke  crt_scanf, addr tpi, addr c_
    inc byte ptr [entrv]
    invoke  crt_printf, addr tp2, addr entr
    invoke  crt_scanf, addr tpi, addr d
    mov eax, [c_]
    sub eax, [d]        ;c-d
    imul    eax, [b]        ;b*(c-d)
    mov [a], eax        ;a=b*(c-d)
    dec [d]         ;d-1
    mov eax, [c_]
    cdq
    idiv    [d]         ;c/d-a
    sub [a],eax         ;b*(c-d)-c/(d-1)
    invoke  crt_printf, addr rs, [a]
    invoke  crt__getch
    invoke  crt_exit,0
    end start