/* Micro-C Code Generatation Part for intel386 */
/* $Id$ */

#define EXTERN extern
#include "mc.h"

#define REGISTERS6   0

extern int  get_register_var(void);
extern void bexpr(int e1, char cond, int l1);
extern void closing(void);
extern void cmpdimm(int e, int csreg);
extern void code_enter(char *name) ;
extern void code_enter1(int disp0,int args);
extern void code_init(void);
extern void code_leave(char *name) ;
extern void def_label(int cslabel, int dlabel) ;
extern void emit_data(int e, int t, NMTBL *n);
extern void emit_init(void);
extern void enter(char *name) ;
extern void enter1(int disp) ;
extern void g_expr(int e1);
extern void gen_comment(char *s);
extern void gen_gdecl(char *n, int gpc) ;
extern void gen_source(char *s);
extern void gexpr(int e1);
extern void jcond(int l, char cond);
extern void jmp(int l);
extern void opening(char *filename);
extern void ret(void);

static char *div_setup(int oreg) ;
static int	lvar(int l);
static void	jump(int e1, int env);
static void    data_mode(char *name);
static void    text_mode(void);
static void assign(int e1);
static void assop(int e1);
static void b_expr(int e1, char cond, int l1);
static void emit_push(void);
static void free_register(int i);
static void function(int e1);
static void global_table(void) ;
/* static void indexy(char *op, char *gvar); */
/* static void jmp_eq_label(int l); */
/* static void jmp_label(int l); */
static void ld_indexx(int byte, int n, int xreg);
static void local_table(void) ;
static void machinop(int e1);
static void rexpr(int e1, int l1, char *s);
static void rindirect(int e1);
static void sassign(int e1);
static void shift(char *op, int xreg) ;
/* static void st_indexx(int byte, int n, int xreg); */
static void string(int e1);
static void tosop(int op);
void div_cleanup(char *orn);

extern int cadr(int e);
extern int car(int e);
extern int caddr(int e);
extern int cadddr(int e);
extern int error(int n);
extern int fwdlabel(void);
extern void fwddef(int l);
extern int backdef(void);
extern int size(int t);
extern int list3(int e1, int e2, int e3);
extern int scalar(int);
extern int reverse0(int);

#define TEXT_EMIT_MODE 0
#define DATA_EMIT_MODE 1
#define RODATA_EMIT_MODE 2

static int output_mode = TEXT_EMIT_MODE;
static int data_alignment = 0;

/*
         local1 <----24 local variable
        %esi        -20  <- disp_offset
        %edi        -16
        %edx        -12
        %ecx         -8
        %ebx         -4
        %ebp = %esp   0
        %eip          4   <- arg_offset
          arg1        8
            see enter/enter1/leave
 */
int arg_offset = 8;
int code_arg_offset = -4;
int disp_offset = -12;
int func_disp_offset = -12;
int code_disp_offset = -4;
int size_of_int = 4;
int endian = 0;
int MAX_REGISTER=6;         /* intel386のレジスタを4つまで使う*/
int REAL_MAX_REGISTER=8;    /* intel386のレジスタが8つということ*/
int MAX_DATA_REG=4;    
int MAX_POINTER=3;    
int MAX_REGISTGER_VAR=2;    

static int  creg;     /* current register */
static int  lreg;     /* operand register */
static int  dreg;     /* temporary register */
static int  reg_sp;   /* REGister Stack-Pointer */


#define REG_EAX   0
#define REG_EBX   1
#define REG_ECX   2
#define REG_EDX   3
#define REG_ESI   4
#define REG_EDI   5
#define REG_EBP   6
#define REG_ESP   7


#define DATA_REG 0    
#define POINTER_REG 3    
static char *reg_name[8]; 
static char *reg_name_l[4];
static char *reg_name_w[4];

/*
    creg   currrent virtual register
    lreg   operand virtual register
    dreg   spare virtual register

    rname[creg]   currrent real register
    rname[lreg]   operand real register
    rname[dreg]   spare real register

    regs[]        virtual register usage

    reg_name[rname[creg]]
 */

#define MAX_MAX 10
static int rname[MAX_MAX];
static int regs[MAX_MAX];       /* 使われているレジスタを示すフラグ */
static int reg_stack[MAX_MAX];  /* 実際のレジスタの領域 */

void
code_init(void)
{
    if (REGISTERS6) {
	arg_offset = 8;
	func_disp_offset = -20;
	disp_offset = -20;
	size_of_int = 4;
	endian = 0;
	MAX_REGISTER=6;
	MAX_DATA_REG=4;    
	MAX_POINTER=3;    
    } else {
	arg_offset = 8;
	func_disp_offset = -12;
	disp_offset = -12;
	size_of_int = 4;
	endian = 0;
	MAX_REGISTER=4;
	MAX_DATA_REG=4;    
	MAX_POINTER=1;    
    }
    MAX_REGISTER_VAR=2;    

    reg_name[REG_EAX] = "%eax";
    reg_name[REG_EBX] = "%ebx";
    reg_name[REG_ECX] = "%ecx";
    reg_name[REG_EDX] = "%edx";
    reg_name[REG_ESI] = "%esi";
    reg_name[REG_EDI] = "%edi";
    reg_name[REG_EBP] = "%ebp";
    reg_name[REG_ESP] = "%esp";
    reg_name_l[REG_EAX] = "%al";
    reg_name_l[REG_EBX] = "%bl";
    reg_name_l[REG_ECX] = "%cl";
    reg_name_l[REG_EDX] = "%dl";
    reg_name_w[REG_EAX] = "%ax";
    reg_name_w[REG_EBX] = "%bx";
    reg_name_w[REG_ECX] = "%cx";
    reg_name_w[REG_EDX] = "%dx";

}

char *
register_name(int i,int byte)
{
    if (byte && i <= REG_EDX) {
	return reg_name_l[rname[i]];
    } else {
	return reg_name[rname[i]];
    }
}

int 
get_register(void)
{    /* 使われていないレジスタを調べる */
    int i;
    for(i=0;i<MAX_REGISTER;i++) {
	if (! regs[i]) {    /* 使われていないなら */
	    regs[i]=1;      /* そのレジスタを使うことを宣言し */
	    return i;       /* その場所を表す番号を返す */
	}
    }
    return -1;    /* 空いている場所がないなら、それを表す -1 を返す */
}

void 
free_register(int i) {    /* いらなくなったレジスタを開放 */
    regs[i]=0;
}

int
register_full(void)
{
    int i;
    for(i=0;i<MAX_REGISTER;i++) {
	if (! regs[i]) { 
	    return 0;  
	}
    }
    return 1;    
}

void 
gexpr_init(void)
{
    while(reg_sp > 0) {
	free_register(reg_stack[--reg_sp]);
    }
    text_mode();
}

void 
emit_init(void)
{
    int i;
    for(i=0;i<REAL_MAX_REGISTER;i++) regs[i]=0;
    for(i=0;i<REAL_MAX_REGISTER;i++) rname[i]=i;
    creg = get_register();
    dreg = get_register();
    reg_sp = 0;
    text_mode();
}

int
virtual(int real)
{
    int real_v,i;
    real_v = -1;
    for(i=0;i<MAX_REGISTER;i++) {
	if (rname[i]==real) {
	    real_v=i;
	    break;
	}
    }
    if (real_v == -1)
	error(-1);
    return real_v;
}

void 
use_register(int virt, int real, int move)
{
    int real_v;
    char *move_op;
    if (rname[virt]==real)
	return;
    real_v = virtual(real);
    move_op = regs[real_v]?"\txchg %s,%s\n":"\tmovl %s,%s\n";
    if (move || regs[real_v]) {
	printf(move_op,reg_name[rname[virt]],reg_name[real]);
    } 
    rname[real_v] = rname[virt];
    rname[virt] = real; 
}

void 
use_pointer(int virt, int move)
{
    int i;
    if (rname[virt]>=POINTER_REG)
	return;
    for(i=POINTER_REG;i<MAX_REGISTER;i++) {
	if (!regs[virtual(i)]) {
	    use_register(virt,i,move);
	    return;
	}
    }
    /* we prefer EBX */
    use_register(virt,REG_EBX,move);
}

void 
use_data_reg(int virt, int move)
{
    int i;
    if (rname[virt]<MAX_DATA_REG)
	return;
    for(i=0;i<MAX_DATA_REG;i++) {
	if (!regs[virtual(i)]) {
	    use_register(virt,i,move);
	    return;
	}
    }
    /* we prefer EBX */
    use_register(virt,REG_EBX,move);
}

int 
pop_register(void)
{     /* レジスタから値を取り出す */
    int i,j;

    j = creg;
    i = reg_stack[--reg_sp];

    if(i<0) {
	return i;
    } else {
	free_register(i);
	lreg = i;
	regs[i]=0;
	return lreg;
    }
}

int
stack_used(void) {
    return reg_stack[--reg_sp]<0;
}

void 
emit_push(void)
{
    int new_reg;
    new_reg = get_register();
    if(new_reg<0) {                     /* もうレジスタがない */
	reg_stack[reg_sp++] =  -1;
	printf("\tpushl %s\n",register_name(creg,0));
    } else {
	reg_stack[reg_sp++] = creg;     /* push するかわりにレジスタを使う */
	creg = new_reg;
    }
}

int
emit_pop(int type)
{
    int xreg;
    if (pop_register()==-1) {
	if (type==POINTER_REG)
	    use_pointer(dreg,0);
	else if (type==DATA_REG)
	    use_data_reg(dreg,0);
	printf("\tpopl %s\n",register_name(dreg,0));
	xreg = dreg;
    } else {
	xreg = lreg;
    }
    return xreg;
}

int
get_register_var(void)
{
    int i;
    for(i=REG_ESI;i<REG_ESP;i++) {
	if (! regs[i]) {    /* 使われていないなら */
	    regs[i]=1;      /* そのレジスタを使うことを宣言し */
	    return i;       /* その場所を表す番号を返す */
	}
    }
    return -1;
}

void
gexpr(int e1)
{
    gexpr_init();
    g_expr(e1);
    csvalue = rname[creg]; /* for siwtch value */
}

void
g_expr(int e1)
{
    int e2,e3,e4;
    char *xrn;
    NMTBL *n;

    if (chk) return;
    e2 = cadr(e1);
    switch (car(e1)){
    case GVAR:   
	/* use_pointer(creg,0); */
	printf("\tmovl $%s,%s\n",(char *)caddr(e1),register_name(creg,0));
	return;
    case RGVAR:
	/* use_pointer(creg,0); */
	printf("\tmovl %s,%s\n",(char *)caddr(e1),register_name(creg,0));
	return;
    case CRGVAR:
	printf("\tmovsbl %s,%s\n",(char *)caddr(e1),register_name(creg,1));
	return;
    case LVAR:
	/* use_pointer(creg,0); */
	printf("\tlea %d(%%ebp),%s\n",lvar(e2),register_name(creg,0));
	return;
    case REGISTER:
	/* this is of course redundant... */
	/* we can use rname for this? */
	/* or why not creg=e2? */
	printf("\tmovl %s,%s\n",register_name(e2,0),register_name(creg,0));
	return;
    case RLVAR:
	printf("\tmovl %d(%%ebp),%s\n",lvar(e2),register_name(creg,0));
	return;
    case CRLVAR:
	printf("\tmovsbl %d(%%ebp),%s\n",lvar(e2),register_name(creg,1));
	return;
    case FNAME:
	printf("\tmovl $%s,%s\n",((NMTBL *)e2)->nm,register_name(creg,0));
	return;
    case CONST:  /* 代入する値が0でも特別な処理はしない */
	printf("\tmovl $%d,%s\n",e2,register_name(creg,0));
	return;
    case STRING:
	string(e1);
	return;
    case FUNCTION:
	function(e1);
	return;
    case CODE:
	jump(e2,caddr(e1));
	return;
    case INDIRECT:
	g_expr(e2);
	return;
    case RINDIRECT: case CRINDIRECT:
	rindirect(e1);
	return;
    case ADDRESS:
	g_expr(e2);
	return;
    case MINUS:  /* レジスタに対し、neglを実行すれば実現可能 */
	g_expr(e2);
	/* use_data_reg(creg,1); */
	printf("\tnegl %s\n", register_name(creg,0));
	return;
    case BNOT:   /* ~ */
	g_expr(e2);
	/* use_data_reg(creg,1); */
	printf("\tnotl %s\n", register_name(creg,0));
	return;
    case LNOT:   /* !  */
	g_expr(e2);
	use_data_reg(creg,1);
	xrn = register_name(creg,1);
	printf("\tcmpl $0,%s\n", register_name(creg,0));
	printf("\tsete %s\n", xrn);
	printf("\tmovzbl %s,%s\n", xrn,register_name(creg,0));
	return;
    case PREINC:
	if (car(e2)==REGISTER) {
	    printf("\taddl $%d,%s\n",caddr(e1),register_name(cadr(e2),0));
	    printf("\tmovl %s,%s\n",register_name(cadr(e2),0),register_name(creg,0));
	    return;
	} 
	g_expr(e2);
	xrn = register_name(creg,0);
	printf("\taddl $%d,(%s)\n",caddr(e1),xrn);
	printf("\tmovl (%s),%s\n",xrn,xrn);
	return;
    case POSTINC:
	if (car(e2)==REGISTER) {
	    printf("\tmovl %s,%s\n",register_name(cadr(e2),0),register_name(creg,0));
	    printf("\taddl $%d,%s\n",caddr(e1),register_name(cadr(e2),0));
	    return;
	} 
	g_expr(e2);
	emit_push();  
/* in case of register full we should copy creg to dreg */
	xrn = register_name(emit_pop(0),0);
	printf("\tmovl (%s),%s\n",xrn,register_name(creg,0));
	printf("\taddl $%d,(%s)\n",caddr(e1),xrn);
	return;
    case CPOSTINC:
	/*   char *p; *p++ */
	if (car(e2)==REGISTER) {
	    printf("\tmovl %s,%s\n",register_name(cadr(e2),0),register_name(creg,0));
	    printf("\taddl $%d,%s\n",caddr(e1),register_name(cadr(e2),0));
	    return;
	} 
	g_expr(e2);
	emit_push(); /* in case of register full we should copy creg to dreg */
	xrn = register_name(emit_pop(0),1);
	printf("\tmovsbl (%s),%s\n",xrn,register_name(creg,0));
	printf("\tincl (%s)\n",xrn);
	return;
    case CPREINC:
	if (car(e2)==REGISTER) {
	    printf("\taddl $%d,%s\n",caddr(e1),register_name(cadr(e2),0));
	    printf("\tmovl %s,%s\n",register_name(cadr(e2),0),register_name(creg,0));
	    return;
	} 
	g_expr(e2);
	printf("\tincl (%s)\n",register_name(creg,0));
	printf("\tmovsbl (%s),%s\n",register_name(creg,1),register_name(creg,0));
	return;
    case CPOSTDEC:
	if (car(e2)==REGISTER) {
	    printf("\tmovl %s,%s\n",register_name(cadr(e2),0),register_name(creg,0));
	    printf("\tdecl %s\n",register_name(cadr(e2),0));
	    return;
	} 
	g_expr(e2);
	printf("\tmovsbl (%s),%s\n",register_name(creg,1),register_name(creg,0));
	printf("\tdecl (%s)\n",register_name(creg,0));
	return;
    case CPREDEC:
	if (car(e2)==REGISTER) {
	    printf("\tdecl %s\n",register_name(cadr(e2),0));
	    printf("\tmovl %s,%s\n",register_name(cadr(e2),0),register_name(creg,0));
	    return;
	} 
	g_expr(e2);
	emit_push();
	e2 = emit_pop(0);
	printf("\tdecl (%s)\n",register_name(e2,0));
	printf("\tmovsbl (%s),%s\n",register_name(e2,1),register_name(creg,0));
	return;
    case MUL: case UMUL:
    case DIV: case UDIV:	   
    case MOD: case UMOD:
    case LSHIFT: case ULSHIFT: case RSHIFT: case URSHIFT:
    case ADD: case SUB: case BAND: case EOR: case BOR:
	machinop(e1);
	return;
    case COND:
	e2=fwdlabel();
	b_expr(cadr(e1),0,e2);
	g_expr(caddr(e1));
	e4 = rname[creg];
	jmp(e3=fwdlabel());
	fwddef(e2);
	g_expr(cadddr(e1));
	use_register(creg,e4,1);
	fwddef(e3);
	return;
    case SASS: 
	sassign(e1);
	return;
    case ASS: case CASS:
	assign(e1);
	return;
    case ASSOP: case CASSOP:
	assop(e1);
	return;
    case COMMA:
	g_expr(e2);
	g_expr(caddr(e1));
	return;
    case RETURN:
	n = (NMTBL *)e2;
	if (retcont==0)
	    retcont=fwdlabel();
	printf("\tleal _%d,%s\n",retcont,register_name(creg,0));
	return;
    case ENVIRONMENT:
	printf("\tmovl %%ebp,%s\n",register_name(creg,0));
	return;
    default:
	b_expr(e1,1,e2=fwdlabel());  /* including > < ... */
	xrn = register_name(creg,0);
	printf("\txorl %s,%s\n",xrn,xrn);
	jmp(e3=fwdlabel());
	fwddef(e2);
	printf("\tmovl $1,%s\n",xrn);
	fwddef(e3);
    }
}

void
bexpr(int e1, char cond, int l1)
{
    gexpr_init();
    b_expr(e1,cond,l1);
}

void
b_expr(int e1, char cond, int l1)
{
    int e2,l2;
    if (chk) return;
    e2=cadr(e1);
    switch(car(e1)) {
    case LNOT:
	b_expr(e2,!cond,l1);
	return;
    case GT:
	rexpr(e1,l1,cond?"g":"le");
	return;
    case UGT:
	rexpr(e1,l1,cond?"a":"be");
	return;
    case GE:
	rexpr(e1,l1,cond?"ge":"l");
	return;
    case UGE:
	rexpr(e1,l1,cond?"ae":"b");
	return;
    case LT:
	rexpr(e1,l1,cond?"l":"ge");
	return;
    case ULT:
	rexpr(e1,l1,cond?"b":"ae");
	return;
    case LE:
	rexpr(e1,l1,cond?"le":"g");
	return;
    case ULE:
	rexpr(e1,l1,cond?"be":"a");
	return;
    case EQ:
	rexpr(e1,l1,cond?"e":"ne");
	return;
    case NEQ:
	rexpr(e1,l1,cond?"ne":"e");
	return;
    case LAND:
	b_expr(e2,0,cond?(l2=fwdlabel()):l1);
	b_expr(caddr(e1),cond,l1);
	if(cond) fwddef(l2);
	return;
    case LOR:
	b_expr(e2,1,cond?l1:(l2=fwdlabel()));
	b_expr(caddr(e1),cond,l1);
	if(!cond) fwddef(l2);
	return;
    case CRGVAR:
	printf("\tcmpb $0,%s\n",(char *)caddr(e1));
	jcond(l1,cond);
	return;
    case CRLVAR:
	printf("\tcmpb $0,%d(%%ebp)\n",lvar(e2));
	jcond(l1,cond);
	return;
    case RGVAR:
	printf("\tcmpl $0,%s\n",(char *)caddr(e1));
	jcond(l1,cond);
	return;
    case RLVAR:
	printf("\tcmpl $0,%d(%%ebp)\n",lvar(e2));
	jcond(l1,cond);
	return;
    case REGISTER:
	printf("\tcmpl $0,%s\n",register_name(e2,0));
	jcond(l1,cond);
	return;
    case CONST:
	if((cond&&e2)||(!cond&&!e2)) jmp(l1);
	return;
    default:
	g_expr(e1);
	printf("\tcmpl $0,%s\n",register_name(creg,0));
	jcond(l1,cond);
	return;
    }
}

void
ascii(char *s)
{
    printf("\t.string \"");
    while(*s) {
	if (*s=='\n')
	    printf("%cn",92);
	else if (*s<' ')
	    printf("%c%03o",92,*s);
	else if (*s==34)
	    printf("%c%c",92,34);
	else 
	    printf("%c",*s);
	s++;
    }
    printf("%c\n",34);
}

void
string(int e1)
{
    char *s;
    int i,lb;

    if (0) {
	s=(char *)cadr(e1);
	lb=fwdlabel();
	printf("\tjmp _%d\n",lb);
	i=backdef();
	ascii(s);
	printf("\t.align 2\n");
	fwddef(lb);
	printf("\tlea _%d,%s\n",i,register_name(creg,0));
    } else {
	s=(char *)cadr(e1);
	printf(".section\t.rodata\n");
	lb=fwdlabel();
	printf("_%d:\n",lb);
	ascii(s);
	if (output_mode==TEXT_EMIT_MODE) {
	    printf(".text\n");
	} else {
	    text_mode();
	}
	printf("\tlea _%d,%s\n",lb,register_name(creg,0));
    }
}

#define MAX_COPY_LEN 20

void 
emit_copy(char *from,char *to,int length,int offset)
{
    if (length<0) return;
    switch (length) {
    case 0:	break;
    case 1:
	printf("\tmovb %d(%s),%s\n",offset,from, reg_name_l[rname[dreg]] );
	printf("\tmovb %s,%d(%s)\n",reg_name_l[rname[dreg]] ,offset,to);
	break;
    case 2:
	printf("\tmovw %d(%s),%s\n",offset,from, reg_name_w[rname[dreg]] );
	printf("\tmovw %s,%d(%s)\n",reg_name_w[rname[dreg]] ,offset,to);
	break;
    case 4:
	printf("\tmovl %d(%s),%s\n",offset,from, register_name(dreg,0));
	printf("\tmovl %s,%d(%s)\n",register_name(dreg,0), offset,to);
	break;
    default:
	if (length <=MAX_COPY_LEN) {
	    for(;length>=4;length-=4,offset+=4)
		emit_copy(from,to,4,offset);
	    for(;length>=2;length-=2,offset+=2)
		emit_copy(from,to,2,offset);
	    if(length>0)
		emit_copy(from,to,length,offset);
	    return;
	}
	printf("\txchg %%edi,%s\n",from);
	printf("\txchg %%esi,%s\n",to);
	printf("\txchg %%ecx,%s\n",register_name(dreg,0));
	printf("\tmovl $%d,%%ecx\n",length/4);
	printf("\tcld\n\trep\n\tmovsl\n");
	printf("\txchg %%ecx,%s\n",register_name(dreg,0));
	printf("\txchg %%esi,%s\n",to);
	printf("\txchg %%edi,%s\n",from);
	if(length%4) {
	    emit_copy("%esi","%edi",length,offset+length/4);
	}
    }
}

int
struct_push(int e4,int t) 
{
    int length;
    g_expr(e4);
    length=size(t); 
    if(length%size_of_int) {
	length += size_of_int - (length%size_of_int);
    }
    printf("\tsubl $%d,%%esp\n",length);
    if (length<=MAX_COPY_LEN)
	emit_copy(register_name(creg,0),"%esp",length,0);
    else {
	printf("\tpushl %%edi\n");
	printf("\tpushl %%esi\n");
	printf("\tpushl %%ecx\n");
	printf("\tleal 12(%%esp),%%di\n");
	if (rname[creg]!=REG_ESI)
		printf("\tmovl %s,%%esi\n",register_name(creg,0));
	printf("\tmovl $%d,%%ecx\n",length/size_of_int);
	printf("\tcld\n\trep\n\tmovsl\n");
	printf("\tpopl %%ecx\n");
	printf("\tpopl %%esi\n");
	printf("\tpopl %%edi\n");
    }
    return length/size_of_int;
}

void
function(int e1)
{
    int e2,e3,e4,e5,nargs,t;
    NMTBL *n;

    e2 = cadr(e1);
    nargs = 0;
    for (e3 = caddr(e1); e3; e3 = cadr(e3)) {	
	t=caddr(e3);
	n=(NMTBL *)(e5=(cadr(e4 = car(e3))));
	switch(car(e4)) {
	case FNAME:
	    printf("\tlea %s,%s\n",n->nm,register_name(creg,0));
	    printf("\tpushl %s\n",register_name(creg,0));
	    break;
	case ADDRESS:
	    g_expr(e5);
	    printf("\tpushl %s\n",register_name(creg,0));
	    break;
	default:
	    if(scalar(t)) {
		g_expr(e4);
		printf("\tpushl %s\n",register_name(creg,0));
	    } else if (car(t)==STRUCT||car(t)==UNION) {
		nargs += struct_push(e4,t);
		continue;
	    } else {
		error(TYERR);
	    }
	}
	++nargs;
    }
    if (car(e2) == FNAME) {	
	n=(NMTBL *)cadr(e2);
	use_register(creg,REG_EAX,0);
	printf("\tcall\t%s\n",n->nm);
    } else {	
	g_expr(e2);
	use_register(creg,REG_EAX,0);
	printf("\tcall\t*%s\n",register_name(creg,0));
    }
    if (nargs) printf("\taddl $%d,%%esp\n",size_of_int*nargs);
}

int
arg_size(int e3,int *nargs0)
{
    int i,nargs,offset_list,e,t;

    offset_list = 0;
    /* we should use prototypes's type */
    for (i = nargs = 0; e3;e3 =cadr(e3)) {
	e = car(e3); t = caddr(e3);
	if (i < MAX_REGISTER_VAR && scalar(t)) {
	    offset_list = list3(-(REG_ESI+i++),offset_list,e);
	} else {
	    offset_list = 
		list3(nargs,offset_list,e);
	    nargs += (car(e3)==CHAR?size_of_int:size(t));
	}
    }
    *nargs0 = -nargs;
    return offset_list;
}

int
is_simple(int e1) 
{
    int e2 = car(e1);
    return (
	e2==FNAME || e2==LVAR || e2==CRLVAR || e2==REGISTER
    );
}

void
jump_new(int e1, int env)
{
    int e2;
    NMTBL *code0;
/*
      jump アドレスを計算する
 */
    /* compute jump address */
    e2 = cadr(e1);
    if (car(e2) == FNAME) {	
	code0=(NMTBL *)cadr(e2);
	if (code0->sc!=CODE) {
	    error(STERR); return;
	}
    } else {	/* indirect */
	g_expr(e2);
	emit_push();
    }
/*
      まず、複雑な式を前もって単純な式に落す。
      必要なら局所変数を用いる。
      局所変数へのオフセットを覚えておく
 */
/*
      スタックの位置を修正する
 */
/*
      オフセットを用いて、
      並べ変えを行う
 */
/*
      スタックの位置を修正する
 */
/*
      jump code を生成する
 */
}

void
jump(int e1, int env)
{
    int i,args,e2,e3,e4,e5,nargs,regs;
    NMTBL *n,*code0;
    int new_disp,scode,disp1;
    char *xrn;

    /* We need three passes. Compute Stack size, Compute Arg, Copy it. */
    /* count number of args */
    args = caddr(e1);
    args = reverse0(args);
    nargs = arg_size(args,&new_disp);  /* compute in normal order */
    disp1 = (fnptr->sc==CODE)?0:-size_of_int;
    if (new_disp+disp1 < disp) {  /* have to extend stack */
	if (fnptr->sc==CODE)
	    printf("\tleal %d(%%ebp),%%esp\n",new_disp-size_of_int);
	else
	    printf("\tleal %d(%%ebp),%%esp\n",new_disp+disp_offset);
    }
    /* compute jump address */
    e2 = cadr(e1);
    if (car(e2) == FNAME) {	
	code0=(NMTBL *)cadr(e2);
	if (code0->sc!=CODE) {
	    error(STERR); return;
	}
    } else {	/* indirect */
	g_expr(e2);
	emit_push();
    }
    /* compute arguments in reverse order */
/* printf("# jump code_arg_offset=%d code_disp_offset=%d\n",code_arg_offset,code_disp_offset); */
    regs = 0;
    i=MAX_REGISTER_VAR;
    for (e3=nargs; e3;e3 =cadr(e3)) {
	n=(NMTBL *)(e5=(cadr(e4 = caddr(e3))));
	switch(car(e4)) {
	case FNAME:
	    printf("\tlea %s,%s\n",n->nm,register_name(creg,0));
	    emit_push();
	    break;
	case ADDRESS:
	    g_expr(e5);
	    emit_push();
	    break;
	case RLVAR:
	case CRLVAR:
	    if (env==0 && fnptr->sc==CODE) {
/* printf("# e5=%d car(e3)=%d\n",e5,car(e3)); */
		if (e5>=0 && e5==car(e3)) {
		/* The same positioned local variable. No need to copy */
		    reg_stack[reg_sp++] = -2;
		}
		break;
	    }
	    g_expr(e4);
	    emit_push();
	    break;
	case REGISTER:
/* printf("# i=%d rname[e5]=%d\n",i,rname[e5]); */
	    if (i>0 && rname[e5]==REG_ESI+ --i) {
		/* The same register variable. No need to copy */
		reg_stack[reg_sp++] = e5;
		break;
	    }
	default:
	    g_expr(e4);
	    emit_push();
	}
	regs++;
    }
    if (env) {
	/* change the frame pointer */
	g_expr(env);
	printf("\tmovl %s,%%ebp\n",register_name(creg,0));
    } else if (fnptr->sc==FUNCTION) {
	printf("\tlea %d(%%ebp),%%ebp\n",disp_offset);
    } 
    /* force lvar offset mode to CODE */
    scode = fnptr->sc; fnptr->sc = CODE;
/* printf("# jump2 code_arg_offset=%d code_disp_offset=%d\n",code_arg_offset,code_disp_offset); */
    /* copy arguments to destination environment if necessary */
    nargs = reverse0(nargs); /* pop in normal order */
    i=0;
    for (e3=nargs; e3;e3 =cadr(e3)) {
	if ((e4=car(e3))<0)  {
	    /* register case */
	    if (reg_stack[--reg_sp]>=REG_ESI) {
		/* the same registger */
	    } else {
		if(reg_stack[reg_sp]<0) {
		    printf("\tpopl %s\n",reg_name[rname[REG_ESI+i]]); /* e4? */
		} else {
		    printf("\tmovl %s,%s\n",
			    reg_name[rname[reg_stack[reg_sp]]],
			    reg_name[rname[REG_ESI+i]]); /* e4? */
		    free_register(reg_stack[reg_sp]);
		}
		i++;
	    }
	} else {
	    /* local variable case */
	    if (reg_stack[reg_sp-1]== -2) {
		/* same positioned variable */
		reg_sp--;
	    } else {
		printf("\tmovl %s,%d(%%ebp)\n",register_name(emit_pop(0),0), lvar(e4));
	    }
	}
    }
    if (car(e2) != FNAME) {	
	xrn=register_name(emit_pop(0),0);
    }
    if (!env && new_disp+disp1>disp) {
	/* shrink stack if necessary */
	printf("\tleal %d(%%ebp),%%esp\n",new_disp-size_of_int);
    } 
    if (car(e2) == FNAME) {	
	printf("\tjmp %s\n",code0->nm);
    } else {
	printf("\tjmp *%s\n",xrn);
    }
    fnptr->sc = scode;
}


void
machinop(int e1)
{
    int e2,e3,op;

    e2 = cadr(e1);
    op = car(e1);
    e3 = caddr(e1);
    g_expr(e3);
    emit_push();
    g_expr(e2);
    tosop(car(e1));
    return;
}


void
rindirect(int e1)   /* *(p +5 ) */
       
{
    char *op;
    int e2,e3,byte;

    op = ((byte = (car(e1) == CRINDIRECT)) ? "movsbl" : "movl");
    e3 = cadr(e2 = cadr(e1));
    g_expr(e2);
    printf("\t%s (%s),%s\n",op,register_name(creg,byte),register_name(creg,byte));
}

void
sassign(int e1)
{
    int e2,e3,e4,sz;
    char *xrn;

    /* structure assignment */
    e2 = cadr(e1);
    e3 = cadr(e2);
    e4 = caddr(e1);
    sz = size(cadr(e2));  /* cld rep movsb */
    g_expr(e4);
    emit_push();
    g_expr(e2);
    xrn = register_name(emit_pop(0),0);

    return;
}

void
assign(int e1)
{
    char *op;
    int e2,e3,e4,byte;

    op = ((byte=(car(e1) == CASS))? "movb" : "movl");
    /*    e2=e4 */
    e2 = cadr(e1);
    e3 = cadr(e2);
    e4 = caddr(e1);
    switch(car(e2)) {
    case GVAR:      /*   i=3 */
            g_expr(e4);
            if (byte) use_data_reg(creg,1);
            printf("\t%s %s,%s\n",op,register_name(creg,byte),(char *)caddr(e2));
            return;
    case LVAR:
            g_expr(e4);
            if (byte) use_data_reg(creg,1);
            printf("\t%s %s,%d(%%ebp)\n",op,register_name(creg,byte),lvar(cadr(e2)));
            return;
    case REGISTER:
            g_expr(e4);
	    if (creg!=cadr(e2))
		printf("\t%s %s,%s\n",op,register_name(creg,byte),register_name(cadr(e2),0));
            return;
    }
    g_expr(e4);
    emit_push();
    g_expr(e2);
    e2 = emit_pop(0);
    if (byte) use_data_reg(creg,1);
    printf("\t%s %s,(%s)\n",op,register_name(e2,byte),register_name(creg,0));
    printf("\tmovl %s,%s\n",register_name(e2,0),register_name(creg,0));
    return;
}

void
assop(int e1)
{
    int e2,e3,byte,op,new_reg;
    char *xrn;
    int xreg;

    /*   e2 op= e3 */
    byte = (car(e1) == CASSOP);
    e2 = cadr(e1);
    if (car(e2)==INDIRECT) e2=cadr(e2);
    e3 = caddr(e1);
    op = cadddr(e1);

    g_expr(e3);
    emit_push();
    if (car(e2)==REGISTER) {
	new_reg=creg;
	creg = cadr(e2);
	tosop(op);
	creg = new_reg;
	printf("\tmovl %s,%s\n",register_name(cadr(e2),0),register_name(creg,0));
	return;
    }
    g_expr(e2);
    xrn = register_name(xreg = emit_pop(0),0);       /* pop e3 value */
    printf("\tpushl %s   # assop \n",register_name(creg,0));      /* push e2 address */
    ld_indexx(byte,0,creg);
    new_reg = get_register();
    /* push e3 value */
    if(new_reg<0) {                     /* もうレジスタがない */
        reg_stack[reg_sp++] =  -1;
        printf("\tpushl %s\n",xrn);
    } else {
        reg_stack[reg_sp++] = xreg;     /* push するかわりにレジスタを使う */
    }
    tosop(op);
    if(new_reg>=0) free_register(new_reg);
    printf("\tpopl %s   # assop \n",register_name(dreg,0));
    printf("\t%s %s,(%s)\n",byte ? "movb" : "movl",register_name(creg,byte),register_name(dreg,byte));
    return;

}


void
tosop(int op)
{
    int oreg;
    char *orn,*crn;

    oreg = pop_register();
    switch(op) {
    case LSHIFT:
    case ULSHIFT:
	shift("sall",oreg);
	return;
    case RSHIFT:
	shift("sarl",oreg);
	return;
    case URSHIFT:
	shift("shrl",oreg);
	return;
    }
    if(oreg==-1) {
        printf("\tpopl %s\n",register_name(dreg,0));
	oreg = dreg;
    }
    orn = register_name(oreg,0);
    crn = register_name(creg,0);
    switch(op) {
    case ADD:
	printf("\taddl %s,%s\n",orn,crn);
	return;
    case SUB:
	printf("\tsubl %s,%s\n",orn,crn);
	return;
    case BAND: 
	printf("\tandl %s,%s\n",orn,crn);
	return;
    case EOR: 
	printf("\txorl %s,%s\n",orn,crn);
	return;
    case BOR:
	printf("\torl %s,%s\n",orn,crn);
	return;
    case MUL:
    case UMUL:
	/* use_register(dreg,REG_EDX,0); */
	printf("\t%s %s,%s\n","imull",orn,crn);
	return;
    case DIV:
    case UDIV:
	orn = div_setup(oreg);
	if (op==DIV)
	    printf("\tcltd\n\tdivl %s\n",orn);
	else 
	    printf("\txor %%edx,%%edx\n\tidivl %s\n",orn);
	div_cleanup(orn);
	return;
    case MOD:
    case UMOD:
	orn = div_setup(oreg);
	if (op==DIV)
	    printf("\tcltd\n\tdivl %s\n",orn);
	else 
	    printf("\txor %%edx,%%edx\n\tidivl %s\n",orn);
	rname[creg]=REG_EDX;
	rname[dreg]=REG_EAX;
	div_cleanup(orn);
	return;
    }
}

static char *dvi_push = "(%esp)";

char *
div_setup(int oreg)
{
    if (oreg<0) {
	use_register(creg,REG_EAX,1);
	use_register(dreg,REG_EDX,0);
	return 0;
    }
    if (register_full()) {
	printf("\tpushl %s\n",register_name(oreg,0));
	use_register(creg,REG_EAX,1);
	use_register(oreg,REG_EDX,0);
	return dvi_push;
    }
    regs[oreg]=1;
    use_register(creg,REG_EAX,1);
    use_register(dreg,REG_EDX,0);
    regs[oreg]=0;
    return register_name(oreg,0);
}


void
div_cleanup(char *orn)
{
    if (orn==dvi_push)
	printf("\taddl $4,%%esp\n");
}

void
shift(char *op, int reg)
{
    if (reg>=0) {
	use_register(lreg,REG_ECX,1);
    } else {
	use_register(dreg,REG_ECX,0);
	printf("\tpopl %%ecx\n");
    }
    printf("\t%s %%cl,%s\n",op,register_name(creg,0));
}

void
ld_indexx(int byte, int n, int xreg)
{	
    char *op;

    op = byte ? "movsbl" : "movl";
    if (n) 
	    printf("\t%s %d(%s),%s\n",op,n,register_name(xreg,0),register_name(creg,byte));
    else
	    printf("\t%s (%s),%s\n",op,register_name(xreg,0),register_name(creg,byte));
}

/*
void
st_indexx(int byte, int n, int xreg)
{	
    char *op;

    op = byte ? "movb" : "movl";
    if (n) 
	    printf("\t%s %s,%d(%s)\n",op,register_name(creg,byte),n,register_name(xreg,0));
    else
	    printf("\t%s %s,(%s)\n",op,register_name(creg,byte),register_name(xreg,0));
}

void
indexy(char *op, char *gvar)
{
    printf("\t%s %s,%s\n",op,register_name(creg,0),gvar);
}
 */

void
cmpdimm(int e, int csreg)
{
    /* used in dosiwtch() */
    use_register(creg,csreg,0);
    printf("\tcmpl $%d,%s\n",e,register_name(creg,0));
}

void
opening(char *filename)
{
    printf("\t.file \"%s\"\n",filename);
    printf("\t.version\t\"01.01\"\n");
    printf("gcc2_compiled.:\n");
    printf(".text\n");
    emit_init();
}

void
closing(void)
{
    global_table();
    printf("\t.ident \"Micro-C compiled\"\n");
}

/*
void
jmp_label(int l)
{
    printf("\tjmp\t_%d\n",l);
}
 */

/*
void
jmp_eq_label(int l)
{
     printf("\tje\t_%d\n",l);
}
 */

void
rexpr(int e1, int l1, char *s)
{       
    g_expr(list3(SUB,cadr(e1),caddr(e1)));
    printf("\tj%s\t_%d\n",s,l1);
}

void
jcond(int l, char cond)
{       
    printf("\tj%s\t_%d\n",cond?"ne":"e",l);
}

void
jmp(int l)
{       
    control=0;
    printf("\tjmp\t_%d\n",l);
    /* align? */
}

int
fwdlabel(void)
{       
    return labelno++;
}

void
fwddef(int l)
{       
    control=1;
    printf("_%d:\n",l);
}

int
backdef(void)
{       
    control=1;
    printf("_%d:\n",labelno);
    return labelno++;
}

void
def_label(int cslabel, int dlabel)
{
    int fl;

    fl = 0;
    if (control) {
	jmp(fl=fwdlabel());
    }
    fwddef(cslabel);
    if (dlabel)
	jmp(dlabel);
    if (fl) {
	fwddef(fl);
    }
}

void
gen_comment(char *s)
{
     printf("# %s",s);
}

void
gen_source(char *s)
{
     printf("%s",s);
}

void
code_enter(char *name)
{
    printf("\t.align 4\n");
    if (stmode!=STATIC)
	printf(".globl %s\n",name);
    printf("\t.type\t%s,@function\n",name);
    printf("%s:\n",name);
}

void
code_enter1(int disp0,int args)
{
    if(disp0) {
	printf("\tsubl $%d,%%esp\n",-disp0);
    }
printf("# args %d disp %d code_arg_offset=%d code_disp_offset=%d\n",args,disp,code_arg_offset,code_disp_offset); 
}

void
code_leave(char *name)
{
    printf("_%d:\n",labelno);
    printf("\t.size\t%s,_%d-%s\n",name,labelno,name);
    local_table();
    labelno++;
}

void
enter(char *name)
{
    printf("\t.align 2\n");
    if (stmode!=STATIC)
	printf(".globl %s\n",name);
    printf("%s:\n",name);
    printf("\t.type\t%s,@function\n",name);
    printf("\tpushl %%ebp\n");
    printf("\tmovl %%esp,%%ebp\n");
    printf("\tpushl %%ebx\n");
    printf("\tpushl %%ecx\n");
    printf("\tpushl %%edx\n");
    if (REGISTERS6) {
	printf("\tpushl %%edi\n");
	printf("\tpushl %%esi\n");
    }
}

void
enter1(int disp)
{
    if(disp) printf("\tsubl $%d,%%esp\n",-disp);
}

void
leave(int control, char *name)
{
    if (control)
	use_register(creg,REG_EAX,1);
    if (retcont) {
	if (control)
	    jmp(retlabel);
	fwddef(retcont);
	use_register(creg,REG_EAX,0);
	printf("\tmovl %s,%s\n",reg_name[REG_ESI],register_name(creg,0));
	/* printf("\tleave\n"); */
    }
    fwddef(retlabel);
    use_register(creg,REG_EAX,0);
    if (REGISTERS6) {
	printf("\tpopl %%esi\n");
	printf("\tpopl %%edi\n");
    }
    /* if(disp) printf("\taddl $%d,%%esp\n",-disp);  */
    printf("\tlea %d(%%ebp),%%esp\n",disp_offset);
    printf("\tpopl %%edx\n");
    printf("\tpopl %%ecx\n");
    printf("\tpopl %%ebx\n");
    printf("\tleave\n");
    printf("\tret\n");
    printf("_%d:\n",labelno);
    printf("\t.size\t%s,_%d-%s\n",name,labelno,name);
    local_table();
    labelno++;
}


void
ret(void)
{       
    use_register(creg,REG_EAX,1);
    jmp(retlabel); 
}

void
gen_gdecl(char *n, int gpc)
{
    /*
    if (stmode!=STATIC)
	printf(".globl %s\n",n); 
     */
}

void 
align(int t)
{
    if (t!=CHAR) {
	if (data_alignment & 1)
	    printf("\t.align 2\n");
	data_alignment = 0;
    }
}

void
emit_data(int e, int t, NMTBL *n)
{
    int l;
    char *name;
    name = n->nm; 
    if(mode!=GDECL)  { 
	error(-1); return;
    }
    if (n->dsp != -1) {
	n->dsp = -1;   /* initiallized flag */
	printf(".globl\t%s\n",name);
	data_mode(name);
	align(t);
	printf("%s:\n",name); 
    } else {
	data_mode(0);
    }
    if(car(e)==CONST) {       
	if (t==CHAR) {
	    printf("\t.byte %d\n",cadr(e));
	    if (data_alignment>0)
		data_alignment++;
	    gpc += 1;
	} else {
	    printf("\t.long %d\n",cadr(e));
	    gpc += size_of_int;
	}
    } else if(t!=CHAR) {       
	gpc += size_of_int;
	if(car(e)==ADDRESS&&car(cadr(e))==GVAR) {
	    printf("\t.long %s\n",(char *)caddr(cadr(e)));
	} else if(car(e)==FNAME) {
	    printf("\t.long %s\n",((NMTBL *)cadr(e))->nm);
	} else if(car(e)==STRING) {       
	    if (car(n->ty)!=ARRAY || cadr(n->ty)!=CHAR) {
		l = fwdlabel();
		printf("\t.long _%d\n",l);
		printf(".section\t.rodata\n");
		printf("_%d:\n",l);
		output_mode = RODATA_EMIT_MODE;
	    }
	    ascii((char *)cadr(e));
	} else error(TYERR);
    }
}

void
emit_data_closing(NMTBL *n)
{
    int lb;
    if (mode==GDECL) {
	data_mode(0);
	lb=fwdlabel();
	printf("_%d:\n",lb);
	printf("\t.size\t%s,_%d-%s\n",n->nm,lb,n->nm);
    }
}

void
global_table(void)
{
    NMTBL *n;
    int init;
    init=0;
    for(n=ntable;n < &ntable[GSYMS];n++) {
	if (n->sc == GVAR && n->dsp != -1) {
	    /* n->dsp = -1 means initialized global */
	    if (init==0) {
		data_mode(0);
		init=1;
	    }
	    printf(".comm %s,%d\n",n->nm,size(n->ty));
	}
    }
}

void
local_table(void)
{
    NMTBL *n;
    int init;
    init=0;
    /* static local variables */
    for(n=ntable+GSYMS;n < &ntable[GSYMS+LSYMS];n++) {
	if (n->sc == GVAR) {
	    if (init==0) {
		data_mode(0);
		init=1;
	    }
	    printf(".lcomm %s,%d\n",n->nm,size(n->ty));
	}
    }
}

void
text_mode(void)
{
    if (output_mode!=TEXT_EMIT_MODE) {
	printf(".text\n");
	printf("\t.align 2\n");
	output_mode = TEXT_EMIT_MODE;
    }
}

void
data_mode(char *name)
{
    if (output_mode!=DATA_EMIT_MODE) {
	printf(".data\n");
	output_mode = DATA_EMIT_MODE;
    }
    if (name)
	printf("\t.type\t%s,@object\n",name);
}

int
lvar(int l)
{
    if (l<0) {
	if (fnptr->sc==CODE)
	    return l+code_disp_offset;
	else
	    return l+disp_offset;
    } else {
	if (fnptr->sc==CODE)
	    return -l+code_arg_offset;
	else
	    return l+arg_offset;
    }
}

/* end */