#include <stdio.h>
#include <stdlib.h>

typedef	unsigned long	uint32_t;

static	uint32_t	hex_decode(char *p)
{
	uint32_t	val = 0;

	while (1) {
		if (*p >= '0' && *p <= '9') {
			val = (val << 4) | (*p - '0');
		} else if (*p >= 'A' && *p <= 'F') {
			val = (val << 4) | (*p - 'A' + 10);
		} else if (*p >= 'a' && *p <= 'f') {
			val = (val << 4) | (*p - 'a' + 10);
		} else {
			break;
		}

		p++;
	}

	return val;
}

static	void	rdmsr(uint32_t *ecx, uint32_t *eax, uint32_t *edx)
{
#asm
	push	bp
	mov	bp, sp	

	cli			; disable interrupt

	push	eax
	push	ebx
	push	ecx
	push	edx
	push	edi

	mov	bx, [bp+4]	; bp+4:	argument #1 (pointer)
	mov	ecx, [bx]

	mov	edi, #0x9c5a203a	; password of "AMD private MSR"

	rdmsr

	mov	bx, [bp+6]	; bp+6:	argument #2 (pointer)
	mov	[bx], eax
	mov	bx, [bp+8]	; bp+8:	argument #3 (pointer)
	mov	[bx], edx

	pop	edi
	pop	edx
	pop	ecx
	pop	ebx
	pop	eax

	sti			; enable interrupt

	pop	bp
#endasm

	return;
}

int	main(int argc, char *argv[])
{
	int	err;
	uint32_t	ecx, eax, edx, lo, hi, t;

	/* check argument */
	if (argc < 2) {
		printf("usage:	rdmsr [hex value(0-ffffffff)]\n");
		err = EXIT_FAILURE;
		goto fin0;
	}

	/* get MSR index */
	if (argc < 3) {
		lo = hi = hex_decode(argv[1]);
	} else {
		lo = hex_decode(argv[1]);
		hi = hex_decode(argv[2]);
	}

	if (lo > hi) {
		t = lo;
		lo = hi;
		hi = t;
	}

	/* dump MSR value */
	for (ecx = lo; ecx <= hi; ecx++) {
		rdmsr(&ecx, &eax, &edx);
		printf("[%08lx] %08lx:%08lx\n", ecx, edx, eax);
		if (ecx == (uint32_t)0xffffffff) break;	// final value
	}

	err = EXIT_SUCCESS;
 fin0:
	return err;
}