void DoDo(void)
{
char code[MAXMSG];
char l1[MAXLBL];
char l2[MAXLBL];
Match('d');
NewLabel();
strncpy(l1, label, MAXLBL);
NewLabel();
strncpy(l2, label, MAXLBL); // exit point
printf("# DO\n");
Expression(); // expr1 = repeat count
EmitLn("pushl %eax\t\t# repeat count");
PostLabel(l1);
Block(l2);
EmitLn("popl %ecx");
EmitLn("dec %ecx");
EmitLn("pushl %ecx");
// test
snprintf(code, MAXMSG, "jnz .%s", l1);
EmitLn(code);
Match('e'); // ENDWHILE
printf("#ENDDO\n");
PostLabel(l2);
}
void DoIf(char *exit_label)
{
char code[MAXMSG];
char l1[MAXLBL];
char l2[MAXLBL];
Match('i');
printf("# IF\n");
NewLabel();
strncpy(l1, label, MAXLBL);
strncpy(l2, label, MAXLBL);
BoolExpression();
snprintf(code, MAXMSG, "je .%s", l1);
EmitLn(code);
printf("# TRUE\n");
// here, tutorial 05 only matches 'e' once, after the if statement
// this doesn't seem to work unless i add Look=='l' to the test in
// Blocks().
Block(exit_label);
if (Look=='l') {
Match('l');
printf("#ELSE\n");
NewLabel();
strncpy(l2, label, MAXLBL);
snprintf(code, MAXMSG, "jmp .%s", l2);
EmitLn(code);
PostLabel(l1);
Block(exit_label);
}
Match('e'); // ENDIF
printf("#ENDIF\n");
PostLabel(l2);
}
void DoIf()
{
Condition();
char L1[MAX_BUF];
char L2[MAX_BUF];
strcpy(L1, NewLabel());
strcpy(L2, L1);
sprintf(tmp, "jz %s", L1);
EmitLn(tmp);
Block();
if (Token == 'l') {
/* match *else* statement */
strcpy(L2, NewLabel());
sprintf(tmp, "jmp %s", L2);
EmitLn(tmp);
PostLabel(L1);
Block();
}
PostLabel(L2);
MatchString("ENDIF");
}
void DoIf(char *L)
{
char L1[MAX_BUF];
char L2[MAX_BUF];
strcpy(L1, NewLabel());
strcpy(L2, L1);
Match('i');
BoolExpression();
sprintf(tmp, "jz %s", L1);
EmitLn(tmp);
Block(L);
dprint("DoIf: Got Look = %c\n", Look);
if (Look == 'l') {
/* match *else* statement */
Match('l');
strcpy(L2, NewLabel());
sprintf(tmp, "jmp %s", L2);
EmitLn(tmp);
PostLabel(L1);
Block(L);
}
Match('e');
PostLabel(L2);
}
void DoWhile(void)
{
char code[MAXMSG];
char l1[MAXLBL];
char l2[MAXLBL];
Match('w');
NewLabel();
strncpy(l1, label, MAXLBL);
NewLabel();
strncpy(l2, label, MAXLBL);
PostLabel(l1);
BoolExpression();
snprintf(code, MAXMSG, "je .%s", l2);
EmitLn(code);
Block(l2);
Match('e'); // ENDWHILE
printf("#ENDWHILE\n");
snprintf(code, MAXMSG, "jmp .%s", l1);
EmitLn(code);
PostLabel(l2);
}
/* I haven't test the actual generated x86 code here, so you're free to
* inform me if there are bugs. :) */
void DoFor()
{
char L1[MAX_BUF];
char L2[MAX_BUF];
Match('f');
strcpy(L1, NewLabel());
strcpy(L2, NewLabel());
char name = GetName();
Match('=');
Expression();
EmitLn("subl %eax, $1"); /* SUBQ #1, D0*/
sprintf(tmp, "lea %c, %%edx", name);
EmitLn(tmp);
EmitLn("movl %eax, (%edx)");
Expression();
EmitLn("push %eax"); /* save the execution of expression */
PostLabel(L1);
sprintf(tmp, "lea %c, %%edx", name);
EmitLn(tmp);
EmitLn("movl (%edx), %eax");
EmitLn("addl %eax, 1");
EmitLn("movl %eax, (%edx)");
EmitLn("cmp (%esp), %eax");
sprintf(tmp, "jg %s", L2);
EmitLn(tmp);
Block(L2);
Match('e');
sprintf(tmp, "jmp %s", L1);
EmitLn(tmp);
PostLabel(L2);
EmitLn("pop %eax");
}
void DoFor() {
char L1[100];
char L2[100];
Match('f');
strcpy(L1, NewLabel());
strcpy(L2, NewLabel());
char Name = GetName();
Match('=');
Expression();
EmitLn("dec rax");
sprintf(tmp, "mov qword [%c], rax", Name);
EmitLn(tmp);
Expression();
EmitLn("push rax");
PostLabel(L1);
sprintf(tmp, "mov rax, qword [%c]", Name);
EmitLn(tmp);
EmitLn("inc rax");
sprintf(tmp, "mov qword [%c], rax", Name);
EmitLn(tmp);
EmitLn("cmp rax, qword [rsp]");
sprintf(tmp, "jg %s", L2);
EmitLn(tmp);
Block();
Match('e');
sprintf(tmp, "jmp %s", L1);
EmitLn(tmp);
PostLabel(L2);
EmitLn("add rsp, 8");
}
void DoFor(void)
{
char name;
char code[MAXMSG];
char l1[MAXLBL];
char l2[MAXLBL];
Match('f');
printf("# FOR\n");
NewLabel();
strncpy(l1, label, MAXLBL);
NewLabel();
strncpy(l2, label, MAXLBL);
// could call Assignment here, but I need to keep the loop counter handle
name = GetName();
Match('=');
Expression(); // expr1 = initial value
snprintf(code, MAXMSG, "movl $%c,%%edx", name);
EmitLn(code);
EmitLn("movl %eax,(%edx)\t\t# assignment");
Expression(); // expr2 = target value
EmitLn("pushl %eax \t\t # put target count on stack");
// Loop:
PostLabel(l1);
EmitLn("popl %eax \t\t# recover tgt");
EmitLn("pushl %eax");
snprintf(code, MAXMSG, "movl $%c,%%edx", name);
EmitLn(code);
EmitLn("movl (%edx), %ecx \t\t # Grab loop counter");
// test
EmitLn("cmpl %eax, %ecx\t\t# for test");
snprintf(code, MAXMSG, "jg .%s", l2);
EmitLn(code);
Block(l2);
//EmitLn("popl %ecx \t\t# don't need return val");
// loopback
snprintf(code, MAXMSG, "movl $%c,%%edx", name);
EmitLn(code);
EmitLn("movl (%edx), %ecx \t\t # grab loop counter");
EmitLn("inc %ecx \t\t # i++");
EmitLn("movl %ecx, (%edx)");
snprintf(code, MAXMSG, "jmp .%s", l1);
EmitLn(code);
PostLabel(l2);
Match('e'); // ENDWHILE
EmitLn("popl %eax");
printf("#ENDFOR\n");
}
void DoLoop()
{
char L1[MAX_BUF];
char L2[MAX_BUF];
Match('p');
strcpy(L1, NewLabel());
strcpy(L2, NewLabel());
PostLabel(L1);
Block(L2);
Match('e');
sprintf(tmp, "jmp %s", L1);
EmitLn(tmp);
PostLabel(L2);
}
void DoWhile() {
char L1[100];
char L2[100];
strcpy(L1, NewLabel());
strcpy(L2, NewLabel());
PostLabel(L1);
BoolExpression();
BranchFalse(L2);
Block();
MatchString("ENDWHILE");
Branch(L1);
PostLabel(L2);
}
void DoWhile()
{
Next();
char L1[MAX_BUF];
char L2[MAX_BUF];
sprintf(L1, NewLabel());
sprintf(L2, NewLabel());
PostLabel(L1);
BoolExpression();
BranchFalse(L2);
Block();
MatchString("ENDWHILE");
Branch(L1);
PostLabel(L2);
}
void DoRepeat()
{
char L1[MAX_BUF];
char L2[MAX_BUF];
Match('r');
strcpy(L1, NewLabel());
strcpy(L2, NewLabel());
PostLabel(L1);
Block(L2);
Match('u');
BoolExpression();
sprintf(tmp, "jz %s", L1);
EmitLn(tmp);
PostLabel(L2);
}
void DoBlock(char Name) {
Declarations();
sprintf(tmp, "%c", Name);
PostLabel("main");
EmitLn("push rbp");
Statements();
}
void DoWhile() {
char L1[100];
char L2[100];
Match('w');
strcpy(L1, NewLabel());
strcpy(L2, NewLabel());
PostLabel(L1);
BoolExpression();
sprintf(tmp, "jz %s", L2);
EmitLn(tmp);
Block();
Match('e');
sprintf(tmp, "jmp %s", L1);
EmitLn(tmp);
PostLabel(L2);
}
void DoIf() {
char L1[100];
char L2[100];
BoolExpression();
strcpy(L1, NewLabel());
strcpy(L2, L1);
BranchFalse(L1);
Block();
if(Token == 'l') {
Match('l');
strcpy(L2, NewLabel());
Branch(L2);
PostLabel(L1);
Block();
}
PostLabel(L2);
MatchString("ENDIF");
}
void DoLoop() {
char L[100];
Match('p');
strcpy(L, NewLabel());
PostLabel(L);
Block();
Match('e');
sprintf(tmp, "jmp %s", L);
EmitLn(tmp);
}
void DoDo()
{
Match('d');
char L1[MAX_BUF];
char L2[MAX_BUF];
strcpy(L1, NewLabel());
strcpy(L2, NewLabel());
Expression();
EmitLn("subl %eax, $1");
EmitLn("movl %eax, %ecx");
PostLabel(L1);
EmitLn("pushl %ecx");
Block(L2);
EmitLn("popl %ecx");
sprintf(tmp, "loop %s", L1);
EmitLn(tmp);
EmitLn("pushl %ecx");
PostLabel(L2);
EmitLn("popl %ecx");
}
/* Recognize and Translate an IF construct */
void DoIf()
{
Next();
char L1[MAX_BUF];
char L2[MAX_BUF];
sprintf(L1, NewLabel());
sprintf(L2, L1);
BoolExpression();
BranchFalse(L1);
Block();
if (Token == 'l') {
Next();
sprintf(L2, NewLabel());
Branch(L2);
PostLabel(L1);
Block();
}
PostLabel(L2);
MatchString("ENDIF");
}
void DoRepeat() {
char L[100];
Match('r');
strcpy(L, NewLabel());
PostLabel(L);
Block();
Match('u');
BoolExpression();
sprintf(tmp, "jmp %s", L);
EmitLn(tmp);
}
void DoLoop(void)
{
char code[MAXMSG];
char l1[MAXLBL];
char l2[MAXLBL];
Match('p');
NewLabel();
strncpy(l1, label, MAXLBL);
NewLabel();
strncpy(l2, label, MAXLBL); // exit point
PostLabel(l1);
Block(l2);
Match('e');
snprintf(code, MAXMSG, "jmp .%s", l1);
EmitLn(code);
printf("#ENDLOOP\n");
PostLabel(l2);
}
void DoIf() {
char L1[100];
char L2[100];
Match('i');
BoolExpression();
strcpy(L1, NewLabel());
strcpy(L2, L1);
sprintf(tmp, "jz %s", L1);
EmitLn(tmp);
Block();
if(Look == 'l') {
Match('l');
strcpy(L2, NewLabel());
sprintf(tmp, "jmp %s", L2);
EmitLn(tmp);
PostLabel(L1);
Block();
}
Match('e');
PostLabel(L2);
}
void DoRepeat(void)
{
char code[MAXMSG];
char l1[MAXLBL];
char l2[MAXLBL];
Match('r');
printf("# REPEAT\n");
NewLabel();
strncpy(l1, label, MAXLBL);
NewLabel();
strncpy(l2, label, MAXLBL);
PostLabel(l1);
Block(l2);
Match('u');
printf("# UNTIL\n");
BoolExpression();
snprintf(code, MAXMSG, "je .%s\t\t#repeat loop", l1);
EmitLn(code);
PostLabel(l2); // exit point
}
void DoBlock(char name){
Declarations();
PostLabel(name);
Statements();
}
void Prolog() {
EmitLn("section .text");
EmitLn("global main");
PostLabel("main");
EmitLn("push rbp");
}
