From cf9ceecb2f8cad2fb694b15c14ca1cf98e9524e7 Mon Sep 17 00:00:00 2001
From: Rui Ueyama <ruiu@cs.stanford.edu>
Date: Tue, 22 Sep 2020 18:28:37 +0900
Subject: [PATCH] Add flonum ==, !=, < and <=

---
 codegen.c    | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 test/float.c | 20 ++++++++++++++++++++
 type.c       |  5 +++++
 3 files changed, 74 insertions(+)

diff --git a/codegen.c b/codegen.c
index fb3f806..a775136 100644
--- a/codegen.c
+++ b/codegen.c
@@ -34,6 +34,18 @@ static void pop(char *arg) {
   depth--;
 }
 
+static void pushf(void) {
+  println("  sub $8, %%rsp");
+  println("  movsd %%xmm0, (%%rsp)");
+  depth++;
+}
+
+static void popf(char *arg) {
+  println("  movsd (%%rsp), %s", arg);
+  println("  add $8, %%rsp");
+  depth--;
+}
+
 // Round up `n` to the nearest multiple of `align`. For instance,
 // align_to(5, 8) returns 8 and align_to(11, 8) returns 16.
 int align_to(int n, int align) {
@@ -403,6 +415,43 @@ static void gen_expr(Node *node) {
   }
   }
 
+  if (is_flonum(node->lhs->ty)) {
+    gen_expr(node->rhs);
+    pushf();
+    gen_expr(node->lhs);
+    popf("%xmm1");
+
+    char *sz = (node->lhs->ty->kind == TY_FLOAT) ? "ss" : "sd";
+
+    switch (node->kind) {
+    case ND_EQ:
+    case ND_NE:
+    case ND_LT:
+    case ND_LE:
+      println("  ucomi%s %%xmm0, %%xmm1", sz);
+
+      if (node->kind == ND_EQ) {
+        println("  sete %%al");
+        println("  setnp %%dl");
+        println("  and %%dl, %%al");
+      } else if (node->kind == ND_NE) {
+        println("  setne %%al");
+        println("  setp %%dl");
+        println("  or %%dl, %%al");
+      } else if (node->kind == ND_LT) {
+        println("  seta %%al");
+      } else {
+        println("  setae %%al");
+      }
+
+      println("  and $1, %%al");
+      println("  movzb %%al, %%rax");
+      return;
+    }
+
+    error_tok(node->tok, "invalid expression");
+  }
+
   gen_expr(node->rhs);
   push();
   gen_expr(node->lhs);
diff --git a/test/float.c b/test/float.c
index c41e4ae..082a9fa 100644
--- a/test/float.c
+++ b/test/float.c
@@ -39,6 +39,26 @@ int main() {
 
   ASSERT(-2147483648, (double)(unsigned long)(long)-1);
 
+  ASSERT(1, 2e3==2e3);
+  ASSERT(0, 2e3==2e5);
+  ASSERT(1, 2.0==2);
+  ASSERT(0, 5.1<5);
+  ASSERT(0, 5.0<5);
+  ASSERT(1, 4.9<5);
+  ASSERT(0, 5.1<=5);
+  ASSERT(1, 5.0<=5);
+  ASSERT(1, 4.9<=5);
+
+  ASSERT(1, 2e3f==2e3);
+  ASSERT(0, 2e3f==2e5);
+  ASSERT(1, 2.0f==2);
+  ASSERT(0, 5.1f<5);
+  ASSERT(0, 5.0f<5);
+  ASSERT(1, 4.9f<5);
+  ASSERT(0, 5.1f<=5);
+  ASSERT(1, 5.0f<=5);
+  ASSERT(1, 4.9f<=5);
+
   printf("OK\n");
   return 0;
 }
diff --git a/type.c b/type.c
index 7bcec3d..358919f 100644
--- a/type.c
+++ b/type.c
@@ -73,6 +73,11 @@ static Type *get_common_type(Type *ty1, Type *ty2) {
   if (ty1->base)
     return pointer_to(ty1->base);
 
+  if (ty1->kind == TY_DOUBLE || ty2->kind == TY_DOUBLE)
+    return ty_double;
+  if (ty1->kind == TY_FLOAT || ty2->kind == TY_FLOAT)
+    return ty_float;
+
   if (ty1->size < 4)
     ty1 = ty_int;
   if (ty2->size < 4)