环境说明

RealView MDK3.05以上

分析描述

代码如下： int func (int val) { __asm { MOV R7,0xFFFF0000 MOV R0,R0,LSL #16 ADD R0,R0,R1 } return val; } 错误提示： warning: #1267-D: Implicit physical register R7 should be defined as a variable warning: #1267-D: Implicit physical register R0 should be defined as a variable error: #549: variable "R0" is used before its value is set warning: #1267-D: Implicit physical register R1 should be defined as a variable error: #549: variable "R1" is used before its value is set warning: #177-D: variable "val2" was declared but never referenced

问题解答

      问题解决：由于嵌套过程中会出现寄存器冲突
      正确例程：
      int func (int val)  {
      int val2;
      __asm
          {
            MOV val2,0xFFFF0000
            MOV val,val,LSL #16
          }
          return val+val2;
         }