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我是 ARM 汇编的新手，我想在内联汇编中实现我的 C 函数之一。我的函数是多精度乘法，它将 32 位无符号整数与 256 位无符号整数相乘，并将结果放入 288 位无符号整数数据类型。我将我的数据类型定义为：

typedef struct UN_256fe{

uint32_t uint32[8];

}UN_256fe;

typedef struct UN_288bite{

uint32_t uint32[9];

}UN_288bite;

这是我的功能：

void multiply32x256(uint32_t A, UN_256fe* B, UN_288bite* res){
uint32_t temp;
asm (    "umull         %0, %1, %9, %10;\n\t"
         "umull         %18, %2, %9, %11;\n\t"
         "adds          %1, %18, %1;    \n\t"
         "umull         %18, %3, %9, %12;\n\t"
         "adcs          %2, %18, %2;    \n\t"
         "umull         %18, %4, %9, %13;\n\t"
         "adcs          %3, %18, %3;    \n\t"
         "umull         %18, %5, %9, %14;\n\t"
         "adcs          %4, %18, %4;    \n\t"
         "umull         %18, %6, %9, %15;\n\t"
         "adcs          %5, %18, %5;    \n\t"
         "umull         %18, %7, %9, %16;\n\t"
         "adcs          %6, %18, %6;    \n\t"
         "umull         %18, %8, %9, %17;\n\t"
         "adcs          %7, %18, %7;    \n\t"
         "adc           %8, %8, 0 ;     \n\t"

         : "=r"(res->uint32[8]), "=r"(res->uint32[7]), "=r"(res->uint32[6]), "=r"(res->uint32[5]), "=r"(res->uint32[4]),
           "=r"(res->uint32[3]), "=r"(res->uint32[2]), "=r"(res->uint32[1]), "=r"(res->uint32[0])
         : "r"(A), "r"(B->uint32[7]), "r"(B->uint32[6]), "r"(B->uint32[5]),
           "r"(B->uint32[4]), "r"(B->uint32[3]), "r"(B->uint32[2]), "r"(B->uint32[1]), "r"(B->uint32[0]), "r"(temp));

}

对我来说似乎很好。但是当我调试我的代码时，例如在执行后的第一行， "umull %0, %1, %9, %10;\n\t" 我有：

(gdb) p/x A //-->%9
$8 = 0x1
(gdb) p/x B->uint32[7] //-->%10
$9 = 0xffffff1
(gdb) p/x res->uint32[8] //-->%0
$10 = 0x1
(gdb) p/x res->uint32[7] //-->%1
$11 = 0x0

看来我在组装说明中犯了一些错误。谁能给我解释一下？

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