msp430 iar 堆栈分析常量数组优化

最新推荐文章于 2025-03-26 17:04:30 发布

xing_chang

最新推荐文章于 2025-03-26 17:04:30 发布

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分类专栏： C/C++ MSP430

本文链接：https://blog.youkuaiyun.com/xing_chang/article/details/8232775

常量数组定义在函数内部时，函数运行时需要将常量数组拷贝到堆栈，浪费了堆栈空间，还增加了函数#?CopyMemoryBytes的时间开销。所以对于数组常量建议存储于函数外部，当然这仅限于430的iar编译器，别的情况就要实际运行一下看了。

对比分析：

常量数组定义在函数内部

static void updata_lead_num(void)             
{   
    UINT8 const Dsp_Lead[12][4] = { "V1 ","V2 ","V3 ","V4 ","V5 ","V6 ",
    "I  ","II ","III","aVL","aVR","aVF" };
    _DINT();//关总中断 
    LCD_WRITE_STRING86(7,9,0,Dsp_Lead[LeadNum]);
    _EINT();//开总中断 
}

对应汇编

static void updata_lead_num(void)             
{   
updata_lead_num:
 00A150    8031 0030          sub.w   #0x30,SP
    UINT8 const Dsp_Lead[12][4] = { "V1 ","V2 ","V3 ","V4 ","V5 ","V6 ",
    "I  ","II ","III","aVL","aVR","aVF" };
 00A154    410C               mov.w   SP,R12
 00A156    403E 4897          mov.w   #0x4897,R14
 00A15A    403D 0030          mov.w   #0x30,R13
 00A15E    13B0 A824          calla   #?CopyMemoryBytes
    _DINT();//关总中断 
 0