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#include "lisc.h"
enum { SLong, SWord, SShort, SByte };
static char *rsub[][4] = {
[RXX] = {"BLACK CAT", "BROKEN MIRROR", "666", "NOOOO!"},
[RAX] = {"rax", "eax", "ax", "al"},
[RBX] = {"rbx", "ebx", "bx", "bl"},
[RCX] = {"rcx", "ecx", "cx", "cl"},
[RDX] = {"rdx", "edx", "dx", "dl"},
[RSI] = {"rsi", "esi", "si", "sil"},
[RDI] = {"rdi", "edi", "di", "dil"},
[RBP] = {"rbp", "ebp", "bp", "bpl"},
[RSP] = {"rsp", "esp", "sp", "spl"},
[R8 ] = {"r8" , "r8d", "r8w", "r8b"},
[R9 ] = {"r9" , "r9d", "r9w", "r9b"},
[R10] = {"r10", "r10d", "r10w", "r10b"},
[R11] = {"r11", "r11d", "r11w", "r11b"},
[R12] = {"r12", "r12d", "r12w", "r12b"},
[R13] = {"r13", "r13d", "r13w", "r13b"},
[R14] = {"r14", "r14d", "r14w", "r14b"},
[R15] = {"r15", "r15d", "r15w", "r15b"},
};
static char *ctoa[NCmp] = {
[Ceq ] = "e",
[Csle] = "le",
[Cslt] = "l",
[Csgt] = "g",
[Csge] = "ge",
[Cne ] = "ne",
};
static char *
rtoa(int r)
{
if (r < EAX)
return rsub[r][SLong];
else
return rsub[RBASE(r)][SWord];
}
static int
cneg(int cmp)
{
switch (cmp) {
default: diag("cneg: unhandled comparison");
case Ceq: return Cne;
case Csle: return Csgt;
case Cslt: return Csge;
case Csgt: return Csle;
case Csge: return Cslt;
case Cne: return Ceq;
}
}
static void
econ(Con *c, FILE *f)
{
switch (c->type) {
case CAddr:
fprintf(f, "%s", c->label);
if (c->val)
fprintf(f, "%+"PRId64, c->val);
break;
case CNum:
fprintf(f, "%"PRId64, c->val);
break;
default:
diag("econ: invalid constant");
}
}
static void
eref(Ref r, Fn *fn, FILE *f)
{
switch (rtype(r)) {
case RReg:
fprintf(f, "%%%s", rtoa(r.val));
break;
case RSlot:
fprintf(f, "-%d(%%rbp)", 8 * r.val);
break;
case RCon:
fprintf(f, "$");
econ(&fn->con[r.val], f);
break;
default:
diag("emitref: invalid reference");
}
}
static void
emem(Ref r, Fn *fn, FILE *f)
{
switch (rtype(r)) {
default:
diag("emem: invalid memory reference");
case RSlot:
eref(r, fn, f);
break;
case RCon:
econ(&fn->con[r.val], f);
break;
case RReg:
assert(r.val < EAX);
fprintf(f, "(");
eref(r, fn, f);
fprintf(f, ")");
}
}
static void
eop(char *op, Ref a, Ref b, Fn *fn, FILE *f)
{
fprintf(f, "\t%s ", op);
eref(a, fn, f);
if (!req(b, R)) {
fprintf(f, ", ");
eref(b, fn, f);
}
fprintf(f, "\n");
}
static void
eins(Ins i, Fn *fn, FILE *f)
{
static char *otoa[NOp] = {
[OAdd] = "add",
[OSub] = "sub",
[OLoad] = "mov",
[OLoadss] = "movsw",
[OLoadus] = "movzw",
[OLoadsb] = "movsb",
[OLoadub] = "movzb",
};
static char *stoa[] = {
[OStorel - OStorel] = "q",
[OStorew - OStorel] = "l",
[OStores - OStorel] = "w",
[OStoreb - OStorel] = "b",
};
int r;
switch (i.op) {
case OAdd:
case OSub:
if (req(i.to, i.arg[1])) {
if (i.op == OSub) {
eop("neg", i.to, R, fn, f);
eop("add", i.arg[0], i.to, fn, f);
break;
}
i.arg[1] = i.arg[0];
i.arg[0] = i.to;
}
if (!req(i.to, i.arg[0]))
eop("mov", i.arg[0], i.to, fn, f);
eop(otoa[i.op], i.arg[1], i.to, fn, f);
break;
case OCopy:
if (!req(i.arg[0], i.to))
eop("mov", i.arg[0], i.to, fn, f);
break;
case OStorel:
case OStorew:
case OStores:
case OStoreb:
fprintf(f, "\tmov%s ", stoa[i.op - OStorel]);
if (rtype(i.arg[0]) == RReg) {
r = RBASE(i.arg[0].val);
fprintf(f, "%%%s", rsub[r][i.op - OStorel]);
} else
eref(i.arg[0], fn, f);
fprintf(f, ", ");
emem(i.arg[1], fn, f);
fprintf(f, "\n");
break;
case OLoad:
case OLoadss:
case OLoadus:
case OLoadsb:
case OLoadub:
fprintf(f, "\t%s", otoa[i.op]);
if (i.to.val < EAX)
fprintf(f, "q ");
else
fprintf(f, "l ");
emem(i.arg[0], fn, f);
fprintf(f, ", ");
eref(i.to, fn, f);
fprintf(f, "\n");
break;
case OSwap:
eop("xchg", i.arg[0], i.arg[1], fn, f);
break;
case OSign:
if (req(i.to, REG(RDX)) && req(i.arg[0], REG(RAX)))
fprintf(f, "\tcqto\n");
else if (req(i.to, REG(EDX)) && req(i.arg[0], REG(EAX)))
fprintf(f, "\tcltd\n");
else
diag("emit: unhandled instruction (2)");
break;
case OXDiv:
eop("idiv", i.arg[0], R, fn, f);
break;
case OXCmpw:
case OXCmpl:
eop(i.op == OXCmpw ? "cmpl" : "cmpq",
i.arg[0], i.arg[1], fn, f);
break;
case ONop:
break;
default:
if (OXSet <= i.op && i.op <= OXSet1) {
eop("mov $0,", i.to, R, fn, f);
fprintf(f, "\tset%s %%%s\n",
ctoa[i.op-OXSet],
rsub[RBASE(i.to.val)][SByte]);
break;
}
diag("emit: unhandled instruction (3)");
}
}
void
emitfn(Fn *fn, FILE *f)
{
Blk *b, *s;
Ins *i;
int c;
fprintf(f,
".text\n"
".globl liscf\n"
".type liscf, @function\n"
"liscf:\n"
"\tpush %%rbp\n"
"\tmov %%rsp, %%rbp\n"
"\tsub $%u, %%rsp\n",
fn->nspill * 8
);
for (b=fn->start; b; b=b->link) {
fprintf(f, ".L%s:\n", b->name);
for (i=b->ins; i-b->ins < b->nins; i++)
eins(*i, fn, f);
switch (b->jmp.type) {
case JRet:
fprintf(f,
"\tleave\n"
"\tret\n"
);
break;
case JJmp:
if (b->s1 != b->link)
fprintf(f, "\tjmp .L%s\n", b->s1->name);
break;
default:
c = b->jmp.type - JXJc;
if (0 <= c && c <= NCmp) {
if (b->link == b->s2) {
s = b->s1;
} else if (b->link == b->s1) {
c = cneg(c);
s = b->s2;
} else
diag("emit: unhandled jump (1)");
fprintf(f, "\tj%s .L%s\n", ctoa[c], s->name);
break;
}
diag("emit: unhandled jump (2)");
}
}
}
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