#include <limits.h>

#include <string.h>

#include "jit_x86.h"

#include "opcode_helpers.h"

#include "x86_macros.h"

#define NUM_INFO_PARAMS	7

jitoffs_t Write_Execute_Function(JitWriter *jit)

{

	/** 

	 * The variables we're passed in:

	 *  sp_context_t *ctx, uint32_t code_idx, cell_t *result

	 */

	/**

	 * !NOTE!

	 * Currently, we do not accept ctx->frm as the new frame pointer.

	 * Instead, we copy the frame from the stack pointer.

	 * This is because we do not support resuming or sleeping!

	 */

	//push ebp

	//mov ebp, esp

	IA32_Push_Reg(jit, REG_EBP);

	IA32_Mov_Reg_Rm(jit, REG_EBP, REG_ESP, MOD_REG);

	//push esi

	//push edi

	//push ebx

	IA32_Push_Reg(jit, REG_ESI);

	IA32_Push_Reg(jit, REG_EDI);

	IA32_Push_Reg(jit, REG_EBX);

	//sub esp, 4*n	- reserve info array

	//mov esi, esp	- save info pointer

	IA32_Sub_Rm_Imm8(jit, REG_ESP, 4*NUM_INFO_PARAMS, MOD_REG);

	IA32_Mov_Reg_Rm(jit, AMX_REG_INFO, REG_ESP, MOD_REG);

	/* Initial memory setup */

	//mov eax, [ebp+16]		- get result pointer

	//mov [esi+8], eax		- store into info pointer

	//mov eax, [ebp+8]		- get context

	//mov [esi+12], eax		- store context into info pointer

	//mov ecx, [eax+<offs>]	- get heap pointer

	//mov [esi+4], ecx		- store heap into info pointer

	//mov ebp, [eax+<offs>]	- get data pointer

	IA32_Mov_Reg_Rm_Disp8(jit, REG_EAX, REG_EBP, 16);

	IA32_Mov_Rm_Reg_Disp8(jit, AMX_REG_INFO, REG_EAX, AMX_INFO_RETVAL);

	IA32_Mov_Reg_Rm_Disp8(jit, REG_EAX, REG_EBP, 8);

	IA32_Mov_Rm_Reg_Disp8(jit, AMX_REG_INFO, REG_EAX, AMX_INFO_CONTEXT);

	IA32_Mov_Reg_Rm_Disp8(jit, REG_ECX, REG_EAX, offsetof(sp_context_t, hp));

	IA32_Mov_Rm_Reg_Disp8(jit, AMX_REG_INFO, REG_ECX, AMX_INFO_HEAP);

	IA32_Mov_Reg_Rm_Disp8(jit, AMX_REG_DAT, REG_EAX, offsetof(sp_context_t, data));

	/* Frame setup */

	//mov edi, [eax+<offs>]	- get stack pointer

	//add edi, ebp			- relocate to data section

	//mov ebx, edi			- copy sp to frm

	IA32_Mov_Reg_Rm_Disp8(jit, AMX_REG_STK, REG_EAX, offsetof(sp_context_t, sp));

	IA32_Add_Rm_Reg(jit, AMX_REG_STK, AMX_REG_DAT, MOD_REG);

	IA32_Mov_Reg_Rm(jit, AMX_REG_FRM, AMX_REG_STK, MOD_REG);

	/* Info memory setup */

	//mov ecx, [eax+<offs>] - copy memsize to temp var

	//mov [esi+x], ecx		- store unrelocated

	//add ecx, ebp			- relocate

	//mov [esi+x], ecx		- store relocated

	//mov ecx, [eax+<offs>] - get heap low

	//mov [esi+20], ecx		- store heap low into info pointer

	IA32_Mov_Reg_Rm_Disp8(jit, REG_ECX, REG_EAX, offsetof(sp_context_t, memory));

	IA32_Mov_Rm_Reg_Disp8(jit, AMX_REG_INFO, REG_ECX, AMX_INFO_STACKTOP_U);

	IA32_Add_Reg_Rm(jit, AMX_REG_TMP, AMX_REG_DAT, MOD_REG);

	IA32_Mov_Rm_Reg_Disp8(jit, AMX_REG_INFO, REG_ECX, AMX_INFO_STACKTOP);

	IA32_Mov_Reg_Rm_Disp8(jit, REG_ECX, REG_EAX, offsetof(sp_context_t, heapbase));

	IA32_Mov_Rm_Reg_Disp8(jit, AMX_REG_INFO, REG_ECX, AMX_INFO_HEAPLOW);

	/* Remaining needed vars */

	//mov ecx, [esp+(4*(NUM_INFO_PARAMS+3))+12] - get code index (normally esp+12, but we have another array on the stack)

	//add ecx, [eax+<offs>]   - add code base to index

	IA32_Mov_Reg_Esp_Disp8(jit, REG_ECX, 12+(4*(NUM_INFO_PARAMS+3)));

	IA32_Add_Reg_Rm_Disp8(jit, REG_ECX, REG_EAX, offsetof(sp_context_t, codebase));

	/* by now, everything is set up, so we can call into the plugin */

	//call ecx

	IA32_Call_Reg(jit, REG_ECX);

	/* if the code flow gets to here, there was a normal return */

	//mov ecx, [esi+8]		- get retval pointer

	//mov [ecx], eax		- store retval from PRI

	//mov eax, SP_ERR_NONE	- set no error

	IA32_Mov_Reg_Rm_Disp8(jit, REG_ECX, AMX_REG_INFO, AMX_INFO_RETVAL);

	IA32_Mov_Rm_Reg(jit, REG_ECX, AMX_REG_PRI, MOD_MEM_REG);

	IA32_Mov_Reg_Imm32(jit, REG_EAX, SP_ERR_NONE);

	/* save where error checking/halting functions should go to */

	jitoffs_t offs_return = jit->get_outputpos();

	//mov esp, esi			- restore stack pointer

	IA32_Mov_Reg_Rm(jit, REG_ESP, REG_ESI, MOD_REG);

	/* _FOR NOW_ ...

	 * We are going to restore SP, HP, and FRM for now.  This is for 

     * debugging only, to check for alignment errors.  As such:

	 * :TODO: probably remove this.

	 */

	//mov ecx, [esi+context]

	//sub edi, ebp

	//mov edx, [esi+heap]

	//mov [ecx+sp], edi

	//mov [ecx+hp], edx

	IA32_Mov_Reg_Rm_Disp8(jit, REG_ECX, REG_ESI, AMX_INFO_CONTEXT);

	IA32_Sub_Reg_Rm(jit, REG_EDI, REG_EBP, MOD_REG);

	IA32_Mov_Reg_Rm_Disp8(jit, REG_EDX, REG_ESI, AMX_INFO_HEAP);

	IA32_Mov_Rm_Reg_Disp8(jit, REG_ECX, REG_EDI, offsetof(sp_context_t, sp));

	IA32_Mov_Rm_Reg(jit, REG_ECX, REG_EDX, MOD_REG);

	//add esp, 4*NUM_INFO_PARAMS

	//pop ebx

	//pop edi

	//pop esi

	//pop ebp

	//ret

	IA32_Add_Rm_Imm8(jit, REG_ESP, 4*NUM_INFO_PARAMS, MOD_REG);

	IA32_Pop_Reg(jit, REG_EBX);

	IA32_Pop_Reg(jit, REG_EDI);

	IA32_Pop_Reg(jit, REG_ESI);

	IA32_Pop_Reg(jit, REG_EBP);

	IA32_Return(jit);

	return offs_return;

}

void Write_BreakDebug(JitWriter *jit)

{

	//push ecx

	//mov ecx, [esi+ctx]

	//cmp [ecx+dbreak], 0

	//jnz :nocall

	IA32_Push_Reg(jit, AMX_REG_TMP);

	IA32_Mov_Reg_Rm_Disp8(jit, AMX_REG_TMP, AMX_REG_INFO, AMX_INFO_CONTEXT);

	IA32_Cmp_Rm_Disp8_Imm8(jit, AMX_REG_TMP, offsetof(sp_context_t, dbreak), 0);

	jitoffs_t jmp = IA32_Jump_Cond_Imm8(jit, CC_NZ, 0);

	//pushad

	IA32_Pushad(jit);

	//push [esi+frm]

	//push [ecx+context]

	//mov ecx, [ecx+dbreak]

	//call ecx

	//add esp, 8

	//popad

	IA32_Push_Rm_Disp8(jit, AMX_REG_INFO, AMX_INFO_FRAME); //:TODO: move to regs and push? and dont disp for 0

	IA32_Push_Rm_Disp8(jit, AMX_REG_TMP, offsetof(sp_context_t, context));

	IA32_Mov_Reg_Rm_Disp8(jit, AMX_REG_TMP, AMX_REG_TMP, offsetof(sp_context_t, dbreak));

	IA32_Call_Reg(jit, AMX_REG_TMP);

	IA32_Add_Rm_Imm8(jit, REG_ESP, 4*2, MOD_REG);

	IA32_Popad(jit);

	//:nocall

	IA32_Send_Jump8_Here(jit, jmp);

	IA32_Add_Rm_Imm8(jit, REG_ESP, 4*1, MOD_REG);

	IA32_Return(jit);

}

void Write_GetError(JitWriter *jit)

{

	CompData *data = (CompData *)jit->data;

	//mov eax, [esi+info.context]

	//mov eax, [eax+ctx.error]

	//jmp [jit_return]

	IA32_Mov_Reg_Rm_Disp8(jit, REG_EAX, AMX_REG_INFO, AMX_INFO_CONTEXT);

	IA32_Mov_Reg_Rm_Disp8(jit, REG_EAX, REG_EAX, offsetof(sp_context_t, err));

	IA32_Jump_Imm32_Abs(jit, data->jit_return);

}

void Write_SetError(JitWriter *jit, int error)

{

	CompData *data = (CompData *)jit->data;

	//mov eax, <error>

	//jmp [jit_return]

	IA32_Mov_Reg_Imm32(jit, REG_EAX, error);

	IA32_Jump_Imm32_Abs(jit, data->jit_return);

}

void Write_Check_DivZero(JitWriter *jit, jit_uint8_t reg)

{

	//test reg, reg

	//jz :error

	IA32_Test_Rm_Reg(jit, reg, reg, MOD_REG);

	IA32_Jump_Cond_Imm32_Abs(jit, CC_Z, ((CompData *)jit->data)->jit_error_divzero);

}

void Write_CheckHeap_Min(JitWriter *jit)

{

	/* Check if the stack went beyond the heap low.

	 * This usually means there was a compiler error.

	 * NOTE: Special optimization here.

	 * The heap low is always known ahead of time! :)

	 */

	CompData *data = (CompData *)jit->data;

	//cmp [esi+info.heap], <heaplow>

	//jb :error

	IA32_Cmp_Rm_Imm32_Disp8(jit, AMX_REG_INFO, AMX_INFO_HEAP, data->plugin->data_size);

	IA32_Jump_Cond_Imm32_Abs(jit, CC_B, data->jit_error_heapmin);

}

void Write_CheckHeap_Low(JitWriter *jit)

{

	/* Check if the heap is trying to grow beyond the stack.

	 */

	//mov ecx, [esi+info.heap]

	//lea ecx, [ebp+ecx+STACK_MARGIN]

	//cmp ecx, edi

	//ja :error		; I think this is right

	IA32_Mov_Reg_Rm_Disp8(jit, AMX_REG_TMP, AMX_REG_INFO, AMX_INFO_HEAP);

	IA32_Lea_Reg_DispRegMultImm8(jit, AMX_REG_TMP, AMX_REG_DAT, AMX_REG_TMP, NOSCALE, STACK_MARGIN);

	IA32_Cmp_Reg_Rm(jit, AMX_REG_TMP, AMX_REG_STK, MOD_REG);

	IA32_Jump_Cond_Imm32_Abs(jit, CC_A, ((CompData *)jit->data)->jit_error_heaplow);

}

void Write_CheckStack_Min(JitWriter *jit)

{

	/* Check if the stack went beyond the stack top

	 * This usually means there was a compiler error.

	 */

	//cmp edi, [esi+info.stacktop]

	//jae :error

	IA32_Cmp_Reg_Rm_Disp8(jit, AMX_REG_STK, AMX_REG_INFO, AMX_INFO_STACKTOP);

	IA32_Jump_Cond_Imm32_Abs(jit, CC_AE, ((CompData *)jit->data)->jit_error_stackmin);

}

void Write_CheckStack_Low(JitWriter *jit)

{

	/* Check if the stack went beyond the heap boundary.

	 * Unfortunately this one isn't as quick as the other check.

	 * The stack margin check is important for sysreq.n having space.

	 */

	//mov ecx, [esi+info.heap]

	//lea ecx, [ebp+ecx+STACK_MARGIN]

	//cmp edi, ecx

	//jb :error		; I think this is right

	IA32_Mov_Reg_Rm_Disp8(jit, AMX_REG_TMP, AMX_REG_INFO, AMX_INFO_HEAP);

	IA32_Lea_Reg_DispRegMultImm8(jit, AMX_REG_TMP, AMX_REG_DAT, AMX_REG_TMP, NOSCALE, STACK_MARGIN);

	IA32_Cmp_Reg_Rm(jit, AMX_REG_STK, AMX_REG_TMP, MOD_REG);

	IA32_Jump_Cond_Imm32_Abs(jit, CC_B, ((CompData *)jit->data)->jit_error_stacklow);

}

void Write_Check_VerifyAddr(JitWriter *jit, jit_uint8_t reg)

{

	CompData *data = (CompData *)jit->data;

	/* :TODO: Should this be checking for below heaplow?

	 * The old JIT did not.

	 */

	bool call = false;

	if (!(data->inline_level & JIT_INLINE_ERRORCHECKS))

	{

		/* If we're not in the initial generation phase,

		 * Write a call to the actual routine instead.

		 */

		if ((reg == REG_EAX) && data->jit_verify_addr_eax)

		{

			jitoffs_t call = IA32_Call_Imm32(jit, 0);

			IA32_Write_Jump32(jit, call, data->jit_verify_addr_eax);

			return;

		} else if ((reg == REG_EDX) && data->jit_verify_addr_edx) {

			jitoffs_t call = IA32_Call_Imm32(jit, 0);

			IA32_Write_Jump32(jit, call, data->jit_verify_addr_edx);

			return;

		}

		call = true;

	}

	/** 

	 * :TODO: If we can't find a nicer way of doing this,

	 *  then scrap it on high optimizations.  The second portion is not needed at all!

	 */

	/* Part 1: Check if we're in the memory bounds */

	//cmp <reg>, [esi+info.stpu]

	//jae :error

	IA32_Cmp_Reg_Rm_Disp8(jit, reg, AMX_REG_INFO, AMX_INFO_STACKTOP_U);

	IA32_Jump_Cond_Imm32_Abs(jit, CC_AE, ((CompData *)jit->data)->jit_error_memaccess);

	/* Part 2: Check if we're in the invalid region between HP and SP */

	jitoffs_t jmp;

	//cmp <reg>, [esi+info.heap]

	//jb :continue

	//lea ecx, [ebp+<reg>]

	//cmp edi, ecx

	//jb :error

	//:continue

	IA32_Cmp_Reg_Rm_Disp8(jit, reg, AMX_REG_INFO, AMX_INFO_HEAP);

	jmp = IA32_Jump_Cond_Imm8(jit, CC_B, 0);

	IA32_Lea_Reg_DispRegMultImm8(jit, AMX_REG_TMP, AMX_REG_DAT, reg, NOSCALE, 0);

	IA32_Cmp_Reg_Rm(jit, AMX_REG_TMP, AMX_REG_STK, MOD_REG);

	IA32_Jump_Cond_Imm32_Abs(jit, CC_B, ((CompData *)jit->data)->jit_error_memaccess);

	IA32_Send_Jump8_Here(jit, jmp);

	if (call)

	{

		IA32_Return(jit);

	}

}

void Macro_PushN_Addr(JitWriter *jit, int i)

{

	//push eax

	//mov eax, [esi+frm]

	//loop i times:

	// lea ecx, [eax+<val>]

	// mov [edi-4*i], ecx

	//sub edi, 4*N

	//pop eax

	cell_t val;

	int n = 1;

	IA32_Push_Reg(jit, AMX_REG_PRI);

	IA32_Mov_Reg_Rm(jit, AMX_REG_PRI, AMX_REG_INFO, MOD_MEM_REG);

	do

	{

		val = jit->read_cell();

		if (val < SCHAR_MAX && val > SCHAR_MIN)

			IA32_Lea_DispRegImm8(jit, AMX_REG_TMP, AMX_REG_PRI, (jit_int8_t)val);

		else

			IA32_Lea_DispRegImm32(jit, AMX_REG_TMP, AMX_REG_PRI, val);

		IA32_Mov_Rm_Reg_Disp8(jit, AMX_REG_STK, AMX_REG_TMP, -4*n);

	} while (n++ < i);

	IA32_Sub_Rm_Imm8(jit, AMX_REG_STK, 4*i, MOD_REG);

	IA32_Pop_Reg(jit, AMX_REG_PRI);

}

void Macro_PushN_S(JitWriter *jit, int i)

{

	//loop i times:

	// mov ecx, [ebx+<val>]

	// mov [edi-4*i], ecx

	//sub edi, 4*N

	cell_t val;

	int n = 1;

	do 

	{

		val = jit->read_cell();

		if (val < SCHAR_MAX && val > SCHAR_MIN)

			IA32_Mov_Reg_Rm_Disp8(jit, AMX_REG_TMP, AMX_REG_FRM, (jit_int8_t)val);

		else

			IA32_Mov_Reg_Rm_Disp32(jit, AMX_REG_TMP, AMX_REG_FRM, val);

		IA32_Mov_Rm_Reg_Disp8(jit, AMX_REG_STK, AMX_REG_TMP, -4*n);

	} while (n++ < i);

	IA32_Sub_Rm_Imm8(jit, AMX_REG_STK, 4*i, MOD_REG);

}

void Macro_PushN_C(JitWriter *jit, int i)

{

	//loop i times:

	// mov [edi-4*i], <val>

	//sub edi, 4*N

	int n = 1;

	do 

	{

		IA32_Mov_Rm_Imm32_Disp8(jit, AMX_REG_STK, jit->read_cell(), -4*n);

	} while (n++ < i);

	IA32_Sub_Rm_Imm8(jit, AMX_REG_STK, 4*i, MOD_REG);

}

void Macro_PushN(JitWriter *jit, int i)

{

	//loop i times:

	// mov ecx, [ebp+<val>]

	// mov [edi-4*i], ecx

	//sub edi, 4*N

	cell_t val;

	int n = 1;

	do 

	{

		val = jit->read_cell();

		if (val < SCHAR_MAX && val > SCHAR_MIN)

			IA32_Mov_Reg_Rm_Disp8(jit, AMX_REG_TMP, AMX_REG_DAT, (jit_int8_t)val);

		else

			IA32_Mov_Reg_Rm_Disp32(jit, AMX_REG_TMP, AMX_REG_DAT, val);

		IA32_Mov_Rm_Reg_Disp8(jit, AMX_REG_STK, AMX_REG_TMP, -4*n);

	} while (n++ < i);

	IA32_Sub_Rm_Imm8(jit, AMX_REG_STK, 4*i, MOD_REG);

}

void WriteOp_Sysreq_N_Function(JitWriter *jit)

{

	/* The big daddy of opcodes.

	 * eax - num_params

	 * ecx - native index

	 */

	CompData *data = (CompData *)jit->data;

	/* store the number of parameters on the stack */

	//mov [edi-4], eax

	//sub edi, 4

	IA32_Mov_Rm_Reg_Disp8(jit, AMX_REG_STK, REG_EAX, -4);

	IA32_Sub_Rm_Imm8(jit, AMX_REG_STK, 4, MOD_REG);

	/* save registers we will need */

	//push eax	; num_params for stack popping

	//push edx

	IA32_Push_Reg(jit, REG_EAX);

	IA32_Push_Reg(jit, AMX_REG_ALT);

	/* push some callback stuff */

	//push edi		; stack

	//push ecx		; native index

	IA32_Push_Reg(jit, AMX_REG_STK);

	IA32_Push_Reg(jit, REG_ECX);

	/* Relocate stack, heap, frm information, then store back */

	//sub edi, ebp

	//mov ecx, [esi+hea]

	//mov eax, [esi+context]

	//mov [eax+hp], ecx

	//mov [eax+sp], edi

	//mov ecx, [esi+frm]

	//mov [eax+frm], ecx

	IA32_Sub_Rm_Reg(jit, AMX_REG_STK, AMX_REG_DAT, MOD_REG);

	IA32_Mov_Reg_Rm_Disp8(jit, AMX_REG_TMP, AMX_REG_INFO, AMX_INFO_HEAP);

	IA32_Mov_Reg_Rm_Disp8(jit, REG_EAX, AMX_REG_INFO, AMX_INFO_CONTEXT);

	IA32_Mov_Rm_Reg_Disp8(jit, REG_EAX, AMX_REG_TMP, offsetof(sp_context_t, hp));

	IA32_Mov_Rm_Reg_Disp8(jit, REG_EAX, AMX_REG_STK, offsetof(sp_context_t, sp));

	IA32_Mov_Reg_Rm(jit, AMX_REG_TMP, AMX_INFO_FRM, MOD_REG);

	IA32_Mov_Rm_Reg_Disp8(jit, REG_EAX, AMX_REG_TMP, offsetof(sp_context_t, frm));

	/* finally, push the last parameter and make the call */

	//push eax		; context

	//call NativeCallback

	IA32_Push_Reg(jit, REG_EAX);

	jitoffs_t call = IA32_Call_Imm32(jit, 0);

	IA32_Write_Jump32_Abs(jit, call, (void *)&NativeCallback);

	/* Test for error */

	//mov ecx, [esi+context]

	//cmp [ecx+err], 0

	//jnz :error

	IA32_Mov_Reg_Rm_Disp8(jit, AMX_REG_TMP, AMX_REG_INFO, AMX_INFO_CONTEXT);

	IA32_Cmp_Rm_Imm32_Disp8(jit, AMX_REG_TMP, offsetof(sp_context_t, err), 0);

	IA32_Jump_Cond_Imm32_Abs(jit, CC_NZ, data->jit_extern_error);

	/* restore what we damaged */

	//add esp, 4*3

	//add edi, ebp

	//pop edx

	//pop ecx	; num_params

	IA32_Add_Rm_Imm8(jit, REG_ESP, 4*3, MOD_REG);

	IA32_Add_Rm_Reg(jit, AMX_REG_STK, AMX_REG_DAT, MOD_REG);

	IA32_Pop_Reg(jit, AMX_REG_ALT);

	IA32_Pop_Reg(jit, REG_ECX);

	/* pop the AMX stack.  do not check the margins.

	 * Note that this is not a true macro - we don't bother to

	 * set ALT here because nothing will be using it.

	 */

	//lea edi, [edi+ecx*4+4]

	IA32_Lea_Reg_DispRegMultImm8(jit, AMX_REG_STK, AMX_REG_STK, REG_ECX, SCALE4, 4);

	//ret

	IA32_Return(jit);

}