/*
 * Mesa 3-D graphics library
 * Version:  6.5
 *
 * Copyright (C) 2005-2006  Brian Paul   All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/**
 * \file slang_execute_x86.c
 * x86 back end compiler
 * \author Michal Krol, Keith Whitwell
 */

#include "imports.h"
#include "context.h"
#include "colormac.h"
#include "swrast/s_context.h"
#include "slang_execute.h"
#include "slang_library_noise.h"

#if defined(USE_X86_ASM) || defined(SLANG_X86)

#include "x86/rtasm/x86sse.h"

typedef struct
{
	GLuint index;
	GLubyte *csr;
} fixup;

typedef struct
{
	struct x86_function f;
	struct x86_reg r_eax;
	struct x86_reg r_ecx;
	struct x86_reg r_edx;
	struct x86_reg r_esp;
	struct x86_reg r_ebp;
	struct x86_reg r_st0;
	struct x86_reg r_st1;
	struct x86_reg r_st2;
	struct x86_reg r_st3;
	fixup *fixups;
	GLuint fixup_count;
	GLubyte **labels;
	slang_machine *mach;
	GLubyte *l_discard;
	GLubyte *l_exit;
	GLshort fpucntl;
} codegen_ctx;

static GLvoid add_fixup (codegen_ctx *G, GLuint index, GLubyte *csr)
{
	G->fixups = (fixup *) slang_alloc_realloc (G->fixups, G->fixup_count * sizeof (fixup),
		(G->fixup_count + 1) * sizeof (fixup));
	G->fixups[G->fixup_count].index = index;
	G->fixups[G->fixup_count].csr = csr;
	G->fixup_count++;
}

#ifdef NO_FAST_MATH
#define RESTORE_FPU (DEFAULT_X86_FPU)
#define RND_NEG_FPU (DEFAULT_X86_FPU | 0x400)
#else
#define RESTORE_FPU (FAST_X86_FPU)
#define RND_NEG_FPU (FAST_X86_FPU | 0x400)
#endif

static void set_fpu_round_neg_inf (codegen_ctx *G)
{
	if (G->fpucntl != RND_NEG_FPU)
	{
		G->fpucntl = RND_NEG_FPU;
		x87_fnclex (&G->f);
		x86_mov_reg_imm (&G->f, G->r_eax, (GLint) &G->mach->x86.fpucntl_rnd_neg);
		x87_fldcw (&G->f, x86_deref (G->r_eax));
	}
}

static void emit_x87_ex2 (codegen_ctx *G)
{
	set_fpu_round_neg_inf (G);

	x87_fld (&G->f, G->r_st0);	/* a a */
	x87_fprndint (&G->f);		/* int(a) a */
	x87_fld (&G->f, G->r_st0);	/* int(a) int(a) a */
	x87_fstp (&G->f, G->r_st3);	/* int(a) a int(a)*/
	x87_fsubp (&G->f, G->r_st1);/* frac(a) int(a) */
	x87_f2xm1 (&G->f);			/* (2^frac(a))-1 int(a)*/
	x87_fld1 (&G->f);			/* 1 (2^frac(a))-1 int(a)*/
	x87_faddp (&G->f, G->r_st1);/* 2^frac(a) int(a) */
	x87_fscale (&G->f);			/* 2^a */
}

static GLfloat do_ceilf (GLfloat x)
{
	return CEILF (x);
}

static void fetch_texel (GLuint sampler, const GLfloat texcoord[4], GLfloat lambda, GLfloat color[4])
{
	GET_CURRENT_CONTEXT(ctx);
	SWcontext *swrast = SWRAST_CONTEXT(ctx);
	GLchan rgba[4];

	/* XXX: the function pointer is NULL! */
	swrast->TextureSample[sampler] (ctx, ctx->Texture.Unit[sampler]._Current, 1,
		(const GLfloat (*)[4]) texcoord, &lambda, &rgba);
	color[0] = CHAN_TO_FLOAT(rgba[0]);
	color[1] = CHAN_TO_FLOAT(rgba[1]);
	color[2] = CHAN_TO_FLOAT(rgba[2]);
	color[3] = CHAN_TO_FLOAT(rgba[3]);
}

static GLvoid do_vec4_tex2d (GLfloat s, GLfloat t, GLuint sampler, GLfloat *rgba)
{
	GLfloat st[4] = { s, t, 0.0f, 1.0f };

	fetch_texel (sampler, st, 0.0f, rgba);
}

static GLvoid do_print_float (GLfloat x)
{
	_mesa_printf ("slang print: %f\n", x);
}

static GLvoid do_print_int (GLfloat x)
{
	_mesa_printf ("slang print: %d\n", (GLint) x);
}

static GLvoid do_print_bool (GLfloat x)
{
	_mesa_printf ("slang print: %s\n", (GLint) x ? "true" : "false");
}

static GLvoid codegen_assem (codegen_ctx *G, slang_assembly *a)
{
	GLint disp;

	switch (a->type)
	{
	case slang_asm_none:
		break;
	case slang_asm_float_copy:
	case slang_asm_int_copy:
	case slang_asm_bool_copy:
		x86_mov (&G->f, G->r_eax, x86_make_disp (G->r_esp, a->param[0]));
		x86_pop (&G->f, G->r_ecx);
		x86_mov (&G->f, x86_make_disp (G->r_eax, a->param[1]), G->r_ecx);
		break;
	case slang_asm_float_move:
	case slang_asm_int_move:
	case slang_asm_bool_move:
		x86_lea (&G->f, G->r_eax, x86_make_disp (G->r_esp, a->param[1]));
		x86_add (&G->f, G->r_eax, x86_deref (G->r_esp));
		x86_mov (&G->f, G->r_eax, x86_deref (G->r_eax));
		x86_mov (&G->f, x86_make_disp (G->r_esp, a->param[0]), G->r_eax);
		break;
	case slang_asm_float_push:
	case slang_asm_int_push:
	case slang_asm_bool_push:
		/* TODO: use push imm32 */
		x86_mov_reg_imm (&G->f, G->r_eax, *((GLint *) &a->literal));
		x86_push (&G->f, G->r_eax);
		break;
	case slang_asm_float_deref:
	case slang_asm_int_deref:
	case slang_asm_bool_deref:
	case slang_asm_addr_deref:
		x86_mov (&G->f, G->r_eax, x86_deref (G->r_esp));
		x86_mov (&G->f, G->r_eax, x86_deref (G->r_eax));
		x86_mov (&G->f, x86_deref (G->r_esp), G->r_eax);
		break;
	case slang_asm_float_add:
		x87_fld (&G->f, x86_make_disp (G->r_esp, 4));
		x87_fld (&G->f, x86_deref (G->r_esp));
		x87_faddp (&G->f, G->r_st1);
		x86_lea (&G->f, G->r_esp, x86_make_disp (G->r_esp, 4));
		x87_fstp (&G->f, x86_deref (G->r_esp));
		break;
	case slang_asm_float_multiply:
		x87_fld (&G->f, x86_make_disp (G->r_esp, 4));
		x87_fld (&G->f, x86_deref (G->r_esp));
		x87_fmulp (&G->f, G->r_st1);
		x86_lea (&G->f, G->r_esp, x86_make_disp (G->r_esp, 4));
		x87_fstp (&G->f, x86_deref (G->r_esp));
		break;
	case slang_asm_float_divide:
		x87_fld (&G->f, x86_make_disp (G->r_esp, 4));
		x87_fld (&G->f, x86_deref (G->r_esp));
		x87_fdivp (&G->f, G->r_st1);
		x86_lea (&G->f, G->r_esp, x86_make_disp (G->r_esp, 4));
		x87_fstp (&G->f, x86_deref (G->r_esp));
		break;
	case slang_asm_float_negate:
		x87_fld (&G->f, x86_deref (G->r_esp));
		x87_fchs (&G->f);
		x87_fstp (&G->f, x86_deref (G->r_esp));
		break;
	case slang_asm_float_less:
		x87_fld (&G->f, x86_make_disp (G->r_esp, 4));
		x87_fcomp (&G->f, x86_deref (G->r_esp));
		x87_fnstsw (&G->f, G->r_eax);
		/* TODO: use test r8,imm8 */
		x86_mov_reg_imm (&G->f, G->r_ecx, 0x100);
		x86_test (&G->f, G->r_eax, G->r_ecx);
		{
			GLfloat one = 1.0f, zero = 0.0f;
			GLubyte *lab0, *lab1;

			/* TODO: use jcc rel8 */
			lab0 = x86_jcc_forward (&G->f, cc_E);
			x86_mov_reg_imm (&G->f, G->r_ecx, *((GLint *) &one));
			/* TODO: use jmp rel8 */
			lab1 = x86_jmp_forward (&G->f);
			x86_fixup_fwd_jump (&G->f, lab0);
			x86_mov_reg_imm (&G->f, G->r_ecx, *((GLint *) &zero));
			x86_fixup_fwd_jump (&G->f, lab1);
			x86_lea (&G->f, G->r_esp, x86_make_disp (G->r_esp, 4));
			x86_mov (&G->f, x86_deref (G->r_esp), G->r_ecx);
		}
		break;
	case slang_asm_float_equal_exp:
		x87_fld (&G->f, x86_make_disp (G->r_esp, 4));
		x87_fcomp (&G->f, x86_deref (G->r_esp));
		x87_fnstsw (&G->f, G->r_eax);
		/* TODO: use test r8,imm8 */
		x86_mov_reg_imm (&G->f, G->r_ecx, 0x4000);
		x86_test (&G->f, G->r_eax, G->r_ecx);
		{
			GLfloat one = 1.0f, zero = 0.0f;
			GLubyte *lab0, *lab1;

			/* TODO: use jcc rel8 */
			lab0 = x86_jcc_forward (&G->f, cc_E);
			x86_mov_reg_imm (&G->f, G->r_ecx, *((GLint *) &one));
			/* TODO: use jmp rel8 */
			lab1 = x86_jmp_forward (&G->f);
			x86_fixup_fwd_jump (&G->f, lab0);
			x86_mov_reg_imm (&G->f, G->r_ecx, *((GLint *) &zero));
			x86_fixup_fwd_jump (&G->f, lab1);
			x86_lea (&G->f, G->r_esp, x86_make_disp (G->r_esp, 4));
			x86_mov (&G->f, x86_deref (G->r_esp), G->r_ecx);
		}
		break;
	case slang_asm_float_equal_int:
		x86_lea (&G->f, G->r_esp, x86_make_disp (G->r_esp, -4));
		x87_fld (&G->f, x86_make_disp (G->r_esp, a->param[0] + 4));
		x87_fcomp (&G->f, x86_make_disp (G->r_esp, a->param[1] + 4));
		x87_fnstsw (&G->f, G->r_eax);
		/* TODO: use test r8,imm8 */
		x86_mov_reg_imm (&G->f, G->r_ecx, 0x4000);
		x86_test (&G->f, G->r_eax, G->r_ecx);
		{
			GLfloat one = 1.0f, zero = 0.0f;
			GLubyte *lab0, *lab1;

			/* TODO: use jcc rel8 */
			lab0 = x86_jcc_forward (&G->f, cc_E);
			x86_mov_reg_imm (&G->f, G->r_ecx, *((GLint *) &one));
			/* TODO: use jmp rel8 */
			lab1 = x86_jmp_forward (&G->f);
			x86_fixup_fwd_jump (&G->f, lab0);
			x86_mov_reg_imm (&G->f, G->r_ecx, *((GLint *) &zero));
			x86_fixup_fwd_jump (&G->f, lab1);
			x86_mov (&G->f, x86_deref (G->r_esp), G->r_ecx);
		}
		break;
	case slang_asm_float_to_int:
		x87_fld (&G->f, x86_deref (G->r_esp));
		x87_fistp (&G->f, x86_deref (G->r_esp));
		break;
	case slang_asm_float_sine:
		/* TODO: use fsin */
		x86_call (&G->f, (GLubyte *) _mesa_sinf);
		x87_fstp (&G->f, x86_deref (G->r_esp));
		break;
	case slang_asm_float_arcsine:
		/* TODO: use fpatan (?) */
		x86_call (&G->f, (GLubyte *) _mesa_asinf);
		x87_fstp (&G->f, x86_deref (G->r_esp));
		break;
	case slang_asm_float_arctan:
		/* TODO: use fpatan */
		x86_call (&G->f, (GLubyte *) _mesa_atanf);
		x87_fstp (&G->f, x86_deref (G->r_esp));
		break;
	case slang_asm_float_power:
		x87_fld (&G->f, x86_deref (G->r_esp));
		x87_fld (&G->f, x86_make_disp (G->r_esp, 4));
		x87_fyl2x (&G->f);
		emit_x87_ex2 (G);
		x86_lea (&G->f, G->r_esp, x86_make_disp (G->r_esp, 4));
		x87_fstp (&G->f, x86_deref (G->r_esp));
		break;
	case slang_asm_float_log2:
		x87_fld1 (&G->f);
		x87_fld (&G->f, x86_deref (G->r_esp));
		x87_fyl2x (&G->f);
		x87_fstp (&G->f, x86_deref (G->r_esp));
		break;
	case slang_asm_float_floor:
		set_fpu_round_neg_inf (G);
		x87_fld (&G->f, x86_deref (G->r_esp));   
		x87_fprndint (&G->f);   
		x87_fstp (&G->f, x86_deref (G->r_esp));
		break;
	case slang_asm_float_ceil:
		/* TODO: use frndint */
		x86_call (&G->f, (GLubyte *) do_ceilf);
		x87_fstp (&G->f, x86_deref (G->r_esp));
		break;
	case slang_asm_float_noise1:
		x86_call (&G->f, (GLubyte *) _slang_library_noise1);
		x87_fstp (&G->f, x86_deref (G->r_esp));
		break;
	case slang_asm_float_noise2:
		x86_call (&G->f, (GLubyte *) _slang_library_noise2);
		x86_lea (&G->f, G->r_esp, x86_make_disp (G->r_esp, 4));
		x87_fstp (&G->f, x86_deref (G->r_esp));
		break;
	case slang_asm_float_noise3:
		x86_call (&G->f, (GLubyte *) _slang_library_noise4);
		x86_lea (&G->f, G->r_esp, x86_make_disp (G->r_esp, 8));
		x87_fstp (&G->f, x86_deref (G->r_esp));
		break;
	case slang_asm_float_noise4:
		x86_call (&G->f, (GLubyte *) _slang_library_noise4);
		x86_lea (&G->f, G->r_esp, x86_make_disp (G->r_esp, 12));
		x87_fstp (&G->f, x86_deref (G->r_esp));
		break;
	case slang_asm_int_to_float:
		break;
	case slang_asm_int_to_addr:
		x87_fld (&G->f, x86_deref (G->r_esp));
		x87_fistp (&G->f, x86_deref (G->r_esp));
		break;
	case slang_asm_addr_copy:
		x86_pop (&G->f, G->r_eax);
		x86_mov (&G->f, G->r_ecx, x86_deref (G->r_esp));
		x86_mov (&G->f, x86_deref (G->r_ecx), G->r_eax);
		break;
	case slang_asm_addr_push:
		/* TODO: use push imm32 */
		x86_mov_reg_imm (&G->f, G->r_eax, (GLint) a->param[0]);
		x86_push (&G->f, G->r_eax);
		break;
	case slang_asm_addr_add:
		x86_pop (&G->f, G->r_eax);
		x86_add (&G->f, x86_deref (G->r_esp), G->r_eax);
		break;
	case slang_asm_addr_multiply:
		x86_pop (&G->f, G->r_ecx);
		x86_mov (&G->f, G->r_eax, x86_deref (G->r_esp));
		x86_mul (&G->f, G->r_ecx);
		x86_mov (&G->f, x86_deref (G->r_esp), G->r_eax);
		break;
	case slang_asm_vec4_tex2d:
		x86_call (&G->f, (GLubyte *) do_vec4_tex2d);
		x86_lea (&G->f, G->r_ebp, x86_make_disp (G->r_esp, 12));
		break;
	case slang_asm_jump:
		add_fixup (G, a->param[0], x86_jmp_forward (&G->f));
		break;
	case slang_asm_jump_if_zero:
		x86_lea (&G->f, G->r_esp, x86_make_disp (G->r_esp, 4));
		x86_xor (&G->f, G->r_eax, G->r_eax);
		x86_cmp (&G->f, G->r_eax, x86_make_disp (G->r_esp, -4));
		{
			GLubyte *lab0;

			/* TODO: use jcc rel8 */
			lab0 = x86_jcc_forward (&G->f, cc_NE);
			add_fixup (G, a->param[0], x86_jmp_forward (&G->f));
			x86_fixup_fwd_jump (&G->f, lab0);
		}
		break;
	case slang_asm_enter:
		/* FIXME: x86_make_disp(esp, 0) + x86_lea() generates bogus code */
		assert (a->param[0] != 0);
		x86_push (&G->f, G->r_ebp);
		x86_lea (&G->f, G->r_ebp, x86_make_disp (G->r_esp, (GLint) a->param[0]));
		break;
	case slang_asm_leave:
		x86_pop (&G->f, G->r_ebp);
		break;
	case slang_asm_local_alloc:
		/* FIXME: x86_make_disp(esp, 0) + x86_lea() generates bogus code */
		assert (a->param[0] != 0);
		x86_lea (&G->f, G->r_esp, x86_make_disp (G->r_esp, -(GLint) a->param[0]));
		break;
	case slang_asm_local_free:
		/* FIXME: x86_make_disp(esp, 0) + x86_lea() generates bogus code */
		assert (a->param[0] != 0);
		x86_lea (&G->f, G->r_esp, x86_make_disp (G->r_esp, (GLint) a->param[0]));
		break;
	case slang_asm_local_addr:
		disp = -(GLint) (a->param[0] + a->param[1]) + 4;
		if (disp != 0)
		{
			x86_lea (&G->f, G->r_eax, x86_make_disp (G->r_ebp, disp));
			x86_push (&G->f, G->r_eax);
		}
		else
			x86_push (&G->f, G->r_ebp);
		break;
	case slang_asm_global_addr:
		/* TODO: use push imm32 */
		x86_mov_reg_imm (&G->f, G->r_eax, (GLint) &G->mach->mem + a->param[0]);
		x86_push (&G->f, G->r_eax);
		break;
	case slang_asm_call:
		add_fixup (G, a->param[0], x86_call_forward (&G->f));
		break;
	case slang_asm_return:
		x86_ret (&G->f);
		break;
	case slang_asm_discard:
		x86_jmp (&G->f, G->l_discard);
		break;
	case slang_asm_exit:
		x86_jmp (&G->f, G->l_exit);
		break;
	/* mesa-specific extensions */
	case slang_asm_float_print:
		x86_call (&G->f, (GLubyte *) do_print_float);
		break;
	case slang_asm_int_print:
		x86_call (&G->f, (GLubyte *) do_print_int);
		break;
	case slang_asm_bool_print:
		x86_call (&G->f, (GLubyte *) do_print_bool);
		break;
	default:
		assert (0);
	}
}

GLboolean _slang_x86_codegen (slang_machine *mach, slang_assembly_file *file, GLuint start)
{
	codegen_ctx G;
	GLubyte *j_body, *j_exit;
	GLuint i;

	x86_init_func_size (&G.f, 4*1048576);
	G.r_eax = x86_make_reg (file_REG32, reg_AX);
	G.r_ecx = x86_make_reg (file_REG32, reg_CX);
	G.r_edx = x86_make_reg (file_REG32, reg_DX);
	G.r_esp = x86_make_reg (file_REG32, reg_SP);
	G.r_ebp = x86_make_reg (file_REG32, reg_BP);
	G.r_st0 = x86_make_reg (file_x87, 0);
	G.r_st1 = x86_make_reg (file_x87, 1);
	G.r_st2 = x86_make_reg (file_x87, 2);
	G.r_st3 = x86_make_reg (file_x87, 3);
	G.fixups = NULL;
	G.fixup_count = 0;
	G.labels = (GLubyte **) slang_alloc_malloc (file->count * sizeof (GLubyte *));
	G.mach = mach;
	G.fpucntl = RESTORE_FPU;

	mach->x86.fpucntl_rnd_neg = RND_NEG_FPU;
	mach->x86.fpucntl_restore = RESTORE_FPU;

	/* prepare stack and jump to start */
	x86_push (&G.f, G.r_ebp);
	x86_mov_reg_imm (&G.f, G.r_eax, (GLint) &mach->x86.esp_restore);
	x86_push (&G.f, G.r_esp);
	x86_pop (&G.f, G.r_ecx);
	x86_mov (&G.f, x86_deref (G.r_eax), G.r_ecx);
	j_body = x86_jmp_forward (&G.f);

	/* discard keywords go here */
	G.l_discard = x86_get_label (&G.f);
	x86_mov_reg_imm (&G.f, G.r_eax, (GLint) &G.mach->kill);
	x86_mov_reg_imm (&G.f, G.r_ecx, 1);
	x86_mov (&G.f, x86_deref (G.r_eax), G.r_ecx);
	G.l_exit = x86_get_label (&G.f);
	j_exit = x86_jmp_forward (&G.f);

	for (i = 0; i < file->count; i++)
	{
		G.labels[i] = x86_get_label (&G.f);
		if (i == start)
			x86_fixup_fwd_jump (&G.f, j_body);
		codegen_assem (&G, &file->code[i]);
	}

	/* restore stack and return */
	x86_fixup_fwd_jump (&G.f, j_exit);
	x86_mov_reg_imm (&G.f, G.r_eax, (GLint) &mach->x86.esp_restore);
	x86_mov (&G.f, G.r_esp, x86_deref (G.r_eax));
	x86_pop (&G.f, G.r_ebp);
	if (G.fpucntl != RESTORE_FPU)
	{
		x87_fnclex (&G.f);
		x86_mov_reg_imm (&G.f, G.r_eax, (GLint) &G.mach->x86.fpucntl_restore);
		x87_fldcw (&G.f, x86_deref (G.r_eax));
	}
	x86_ret (&G.f);

	/* fixup forward labels */
	for (i = 0; i < G.fixup_count; i++)
	{
		G.f.csr = G.labels[G.fixups[i].index];
		x86_fixup_fwd_jump (&G.f, G.fixups[i].csr);
	}

	slang_alloc_free (G.fixups);
	slang_alloc_free (G.labels);

	/* TODO: free previous instance, if not NULL */
	mach->x86.compiled_func = (GLvoid (*) (slang_machine *)) x86_get_func (&G.f);

	return GL_TRUE;
}

#endif