paizaでインラインアセンブラ その4

概要

paizaで、インラインアセンブラやってみた。
練習問題やってみた。

練習問題

x87、叩け。

参考にしたページ

サンプルコード

#include <stdio.h>
#include <stdint.h>
#include <inttypes.h>
#include <math.h>

#define NUM_OF_ARRAY    (32)
#define M_PI            3.1415926535897932384626433832795

double __attribute__ ((noinline)) fsin(double a) {
  double r;
  __asm__ volatile (
      "movsd    %%xmm0, %0\n" 
      "fldl     %0\n"          
      "fsin     \n"             
      "fstpl    %1\n"         
      :"=m"(a)
      :"m"(r)
    );
    return r;
}

static inline uint64_t RDTSCP() {
  	uint32_t hi, 
		lo, 
		aux;
  	__asm__ volatile("rdtscp" : "=a" (lo), "=d" (hi), "=c" (aux));
  	return ((uint64_t) hi << 32) | lo;
}

static double bufx[NUM_OF_ARRAY + 1];
static double bufs[NUM_OF_ARRAY + 1];
static double bufc[NUM_OF_ARRAY + 1];

int main(int argc, char * argv[]) {
  	uint64_t start, 
		end, 
		diffs, 
		diffc;
  	int count = NUM_OF_ARRAY, 
		i;
  	double xst = -1.0 * M_PI, 
		len = 2.0 * M_PI;
  	for (i = 0; i <= count; i++) 
	{
		double w = len * (double) i / count;
		bufx[i] = xst + w;
  	}
  	start = RDTSCP();
  	for (i = 0; i <= count; i++) 
	{
		bufs[i] = fsin(bufx[i]);
  	}
  	end = RDTSCP();
  	diffs = end - start;
  	start = RDTSCP();
  	for (i = 0; i <= count; i++) 
	{
		bufc[i]  = sin(bufx[i]);
  	}
  	end = RDTSCP();
  	diffc = end - start;
  	printf("x\t\t\tfsin(x)\t\t\tsin(x)\n");
  	for (i = 0; i <= count; i++) 
	{
		printf("%+.16e\t%+.16e\t%+.16e\n", bufx[i], bufs[i], bufc[i]);
  	}
  	printf("fsin tsc %" PRIu64 " sin tsc %" PRIu64 "\n", diffs/NUM_OF_ARRAY, diffc/NUM_OF_ARRAY);
  	return 0;
}

実行結果

x			fsin(x)			sin(x)
-3.1415926535897931e+00	-1.2246063538223773e-16	-1.2246467991473532e-16
-2.9452431127404308e+00	-1.9509032201612861e-01	-1.9509032201612861e-01
-2.7488935718910690e+00	-3.8268343236508989e-01	-3.8268343236508989e-01
-2.5525440310417071e+00	-5.5557023301960218e-01	-5.5557023301960218e-01
-2.3561944901923448e+00	-7.0710678118654757e-01	-7.0710678118654757e-01
-2.1598449493429825e+00	-8.3146961230254546e-01	-8.3146961230254546e-01
-1.9634954084936207e+00	-9.2387953251128674e-01	-9.2387953251128674e-01
-1.7671458676442586e+00	-9.8078528040323043e-01	-9.8078528040323043e-01
-1.5707963267948966e+00	-1.0000000000000000e+00	-1.0000000000000000e+00
-1.3744467859455345e+00	-9.8078528040323043e-01	-9.8078528040323043e-01
-1.1780972450961724e+00	-9.2387953251128674e-01	-9.2387953251128674e-01
-9.8174770424681057e-01	-8.3146961230254535e-01	-8.3146961230254535e-01
-7.8539816339744828e-01	-7.0710678118654746e-01	-7.0710678118654746e-01
-5.8904862254808599e-01	-5.5557023301960207e-01	-5.5557023301960207e-01
-3.9269908169872414e-01	-3.8268343236508978e-01	-3.8268343236508978e-01
-1.9634954084936229e-01	-1.9509032201612847e-01	-1.9509032201612847e-01
+0.0000000000000000e+00	+0.0000000000000000e+00	+0.0000000000000000e+00
+1.9634954084936229e-01	+1.9509032201612847e-01	+1.9509032201612847e-01
+3.9269908169872414e-01	+3.8268343236508978e-01	+3.8268343236508978e-01
+5.8904862254808599e-01	+5.5557023301960207e-01	+5.5557023301960207e-01
+7.8539816339744828e-01	+7.0710678118654746e-01	+7.0710678118654746e-01
+9.8174770424681057e-01	+8.3146961230254535e-01	+8.3146961230254535e-01
+1.1780972450961720e+00	+9.2387953251128652e-01	+9.2387953251128652e-01
+1.3744467859455343e+00	+9.8078528040323043e-01	+9.8078528040323043e-01
+1.5707963267948966e+00	+1.0000000000000000e+00	+1.0000000000000000e+00
+1.7671458676442588e+00	+9.8078528040323043e-01	+9.8078528040323043e-01
+1.9634954084936211e+00	+9.2387953251128663e-01	+9.2387953251128663e-01
+2.1598449493429825e+00	+8.3146961230254546e-01	+8.3146961230254546e-01
+2.3561944901923448e+00	+7.0710678118654757e-01	+7.0710678118654757e-01
+2.5525440310417071e+00	+5.5557023301960218e-01	+5.5557023301960218e-01
+2.7488935718910685e+00	+3.8268343236509028e-01	+3.8268343236509028e-01
+2.9452431127404308e+00	+1.9509032201612861e-01	+1.9509032201612861e-01
+3.1415926535897931e+00	+1.2246063538223773e-16	+1.2246467991473532e-16
fsin tsc 104 sin tsc 1393

成果物

以上。