ezusb的汇编程序改c程序出错，请赐教！

下面是cypress提供的EZBULK.A51

$NOMOD51 ; disable predefined 8051 registers
$nolist
$include (..\..\..\target\inc\ezregs.inc) ; EZ-USB register assignments
$list
;
NAME        ezbulk
;
ISEG AT 60H ; stack (this app doesn't use it)
stack: ds 20
;
CSEG AT 0
  ljmp start
; -------------------------------------------------
org 200h
; -------------------------------------------------
start: mov SP,#STACK-1 ; set stack
mov dptr,#IN2BUF
  mov r7,#64 ; fill EP2IN buffer with 64 bytes
fill: mov a,r7
movx @dptr,a
  inc dptr
   djnz r7,fill ; load decrementing counter starting w. 64
;
mov r1,#0 ; count the IN transfers
  mov r2,#0 ; count the OUT transfers
   mov dptr,#IN2BC ; load the IN2 Byte Count register
   mov a,#64 ; 64 bytes
     movx @dptr,a ; arm the IN transfer
;
loop: mov dptr,#IN2CS ; EP2IN Control & Status register
movx a,@dptr
  jnb acc.1,service_IN2 ; check the busy bit, service if LOW
   mov dptr,#OUT2CS ; EP2OUT Control & Status reg
   movx a,@dptr
     jb acc.1,loop ; busy-keep checking
;
service_OUT2: inc r2 ; OUT packet counter
mov dptr,#IN2BUF+1 ; load OUT packet count into second IN2BUF byte
  mov a,r2
   movx @dptr,a
mov dptr,#OUT2BC ; load anything to byte count to re-arm
  mov a,#1 ; any value
  movx @dptr,a
   sjmp loop
;
service_IN2: inc r1 ; IN packet countr
mov dptr,#IN2BUF
  mov a,r1 ; load IN packet count into first IN2BUF byte
   movx @dptr,a
       mov dptr,#IN2BC ; load the EP2IN byte count to re-arm IN transfer
       mov a,#64 ; 64 byte payload
       movx @dptr,a
       sjmp loop
;
END

自己修改成c之后，编译没有问题，但是运行就是不对

#include <ezusb.h>
#include <ezregs.h>
#include <absacc.h>

main()
{
int r1=0,r2=0,i;
for(i=64;i>0;i--)
IN2BUF[64-i]=i;
IN2BC=64;
while(1)
{
if(!(EPIO[IN2BUF_ID].cntrl & bmEPBUSY))
{
r1++;
IN2BUF[0]=r1;
EPIO[IN2BUF_ID].bytes=64;
}
else if(!(EPIO[OUT2BUF_ID].cntrl & bmEPBUSY))
{
r2++;
IN2BUF[1]=r2;
EPIO[OUT2BUF_ID].bytes=1;
}
}
}
大家帮我看看可能是什么原因？多谢了