--- /dev/null
+#include<stdio.h>
+#include<assert.h>
+
+int main()
+{
+ int rd, rs, rt, dsp;
+ int result, resultdsp;
+
+ rs = 0x12345678;
+ rt = 0x87654321;
+ result = 0x7FFFFFFF;
+ resultdsp = 0x01;
+
+ __asm
+ ("wrdsp $0\n\t"
+ "subq_s.w %0, %2, %3\n\t"
+ "rddsp %1\n\t"
+ : "=r"(rd), "=r"(dsp)
+ : "r"(rs), "r"(rt)
+ );
+ dsp = (dsp >> 20) & 0x01;
+ assert(dsp == resultdsp);
+ assert(rd == result);
+
+ rs = 0x66666;
+ rt = 0x55555;
+ result = 0x11111;
+ resultdsp = 0x0;
+
+ __asm
+ ("wrdsp $0\n\t"
+ "subq_s.w %0, %2, %3\n\t"
+ "rddsp %1\n\t"
+ : "=r"(rd), "=r"(dsp)
+ : "r"(rs), "r"(rt)
+ );
+ dsp = (dsp >> 20) & 0x01;
+ assert(dsp == resultdsp);
+ assert(rd == result);
+
+ rs = 0x0;
+ rt = 0x80000000;
+ result = 0x7FFFFFFF;
+ resultdsp = 0x01;
+
+ __asm
+ ("wrdsp $0\n\t"
+ "subq_s.w %0, %2, %3\n\t"
+ "rddsp %1\n\t"
+ : "=r"(rd), "=r"(dsp)
+ : "r"(rs), "r"(rt)
+ );
+ dsp = (dsp >> 20) & 0x01;
+ assert(dsp == resultdsp);
+ assert(rd == result);
+
+ rs = 0x80000000;
+ rt = 0x80000000;
+ result = 0;
+ resultdsp = 0x00;
+
+ __asm
+ ("wrdsp $0\n\t"
+ "subq_s.w %0, %2, %3\n\t"
+ "rddsp %1\n\t"
+ : "=r"(rd), "=r"(dsp)
+ : "r"(rs), "r"(rt)
+ );
+ dsp = (dsp >> 20) & 0x01;
+ assert(dsp == resultdsp);
+ assert(rd == result);
+
+ return 0;
+}