--- /dev/null
+#include<stdio.h>
+#include<assert.h>
+
+int main()
+{
+ int rd, rs, rt;
+ int dspi, dspo;
+ int result;
+
+ rs = 0x10FF01FF;
+ rt = 0x10010001;
+ dspi = 0x00002000;
+ result = 0x21000201;
+ __asm
+ ("wrdsp %3\n"
+ "addwc %0, %1, %2\n\t"
+ : "=r"(rd)
+ : "r"(rs), "r"(rt), "r"(dspi)
+ );
+ assert(rd == result);
+
+ rs = 0xFFFF1111;
+ rt = 0x00020001;
+ dspi = 0x00;
+ result = 0x00011112;
+ __asm
+ ("wrdsp %3\n"
+ "addwc %0, %1, %2\n\t"
+ : "=r"(rd)
+ : "r"(rs), "r"(rt), "r"(dspi)
+ );
+ assert(rd == result);
+
+ rs = 0x8FFF1111;
+ rt = 0x80020001;
+ dspi = 0x00;
+ result = 0x10011112;
+ __asm
+ ("wrdsp %4\n"
+ "addwc %0, %2, %3\n\t"
+ "rddsp %1\n\t"
+ : "=r"(rd), "=r"(dspo)
+ : "r"(rs), "r"(rt), "r"(dspi)
+ );
+ assert(rd == result);
+ assert(((dspo >> 20) & 0x01) == 1);
+
+ return 0;
+}