commit 425857d4ed72c6e8567c39b17680a100acaad7f8
from: Benjamin Stürz <benni@stuerz.xyz>
date: Mon Oct 07 19:34:16 2024 UTC

irc: improve EX_EQ and EX_NE

commit - 5cf236395aa88dc8f443b83e7a9b79e34a943b8e
commit + 425857d4ed72c6e8567c39b17680a100acaad7f8
blob - 4611deb74a0c263f19dffef9d76504722aa3e8b2
blob + 831bb334e88ec4b53ca52413055e931eb7f39ecd
--- cc/irc/Makefile
+++ cc/irc/Makefile
@@ -7,6 +7,6 @@ clean:
 
 run: all
 	./irc < test.ir > test.asm
-	cat test.asm
 	nasm -fobj -o /dev/null test.asm
+	less test.asm
 
blob - fbd52308aca953b521e52120d240c43707f30f48
blob + bea6a8aacde8acc2be2061524fbcaa04da88d369
--- cc/irc/irc.c
+++ cc/irc/irc.c
@@ -9,6 +9,8 @@
 
 // enable debugging prints
 #define ENABLE_DEBUG 1
+
+int ignore_nan = 0;
 
 // ERROR HANDLING
 
@@ -669,7 +671,7 @@ enum expr_type t;
 	return 0;
 }
 
-expr_cmp (fn, dt, e, t)
+expr_cmp (fn, dt, e, t, allow_fp)
 struct func *fn;
 struct dtype *dt;
 struct expr *e;
@@ -682,7 +684,11 @@ enum expr_type t;
 	regimm (&e->bin.r, &fn->regs[e->bin.l].dt);
 	expect (';');
 
-	assert_dt_is_int (&fn->regs[e->bin.l].dt);
+	if (allow_fp) {
+		assert_dt_is_num (&fn->regs[e->bin.l].dt);
+	} else {
+		assert_dt_is_int (&fn->regs[e->bin.l].dt);
+	}
 	assert_dt_eq (&fn->regs[e->bin.l].dt, e->bin.r.dt);
 	if (dt->type != DT_WORD)
 		error ("result of comparison must be of type word");
@@ -760,25 +766,25 @@ struct expr *e;
 	} else if (strcmp (lval.s, "sdiv") == 0) {
 		expr_bin (fn, dt, e, EX_SDIV, 1);
 	} else if (strcmp (lval.s, "eq") == 0) {
-		expr_cmp (fn, dt, e, EX_EQ);
+		expr_cmp (fn, dt, e, EX_EQ, 1);
 	} else if (strcmp (lval.s, "ne") == 0) {
-		expr_cmp (fn, dt, e, EX_NE);
+		expr_cmp (fn, dt, e, EX_NE, 1);
 	} else if (strcmp (lval.s, "ult") == 0) {
-		expr_cmp (fn, dt, e, EX_ULT);
+		expr_cmp (fn, dt, e, EX_ULT, 0);
 	} else if (strcmp (lval.s, "ugt") == 0) {
-		expr_cmp (fn, dt, e, EX_UGT);
+		expr_cmp (fn, dt, e, EX_UGT, 0);
 	} else if (strcmp (lval.s, "ule") == 0) {
-		expr_cmp (fn, dt, e, EX_ULE);
+		expr_cmp (fn, dt, e, EX_ULE, 0);
 	} else if (strcmp (lval.s, "uge") == 0) {
-		expr_cmp (fn, dt, e, EX_UGE);
+		expr_cmp (fn, dt, e, EX_UGE, 0);
 	} else if (strcmp (lval.s, "slt") == 0) {
-		expr_cmp (fn, dt, e, EX_SLT);
+		expr_cmp (fn, dt, e, EX_SLT, 0);
 	} else if (strcmp (lval.s, "sgt") == 0) {
-		expr_cmp (fn, dt, e, EX_SGT);
+		expr_cmp (fn, dt, e, EX_SGT, 0);
 	} else if (strcmp (lval.s, "sle") == 0) {
-		expr_cmp (fn, dt, e, EX_SLE);
+		expr_cmp (fn, dt, e, EX_SLE, 0);
 	} else if (strcmp (lval.s, "sge") == 0) {
-		expr_cmp (fn, dt, e, EX_SGE);
+		expr_cmp (fn, dt, e, EX_SGE, 0);
 	} else if (strcmp (lval.s, "feq") == 0) {
 		expr_fcmp (fn, dt, e, EX_FEQ);
 	} else if (strcmp (lval.s, "fne") == 0) {
@@ -2020,7 +2026,85 @@ char *cmp, *cc;
 		printf (".Li%d:\n", l1);
 		printf ("\tmov ax, 1\n\n");
 		printf (".Li%d:\n", l2);
+		break;
+	}
+	return 0;
+}
+
+gen_eq (fn, e, inv)
+struct func *fn;
+struct expr *e;
+{
+	int l1, l2;
+
+	switch (e->bin.r.dt->type) {
+	case DT_NONE:
+	case DT_LABEL:
+		abort ();
+		break;
+
+	case DT_BYTE:
+	case DT_WORD:
+	case DT_DPTR:
+	case DT_SPTR:
+		load (NULL, &fn->regs[e->bin.l]);
+		loadri (fn, "cmp", &e->bin.r);
+		puts ("\tlahf");
+		goto common;
+
+	case DT_FPTR:
+	case DT_DWORD:
+		loaddw (NULL, &fn->regs[e->bin.l]);
+		puts ("\t; TODO: adjust loaddw to allow different register pairs");
+		puts ("\tmov bx, ax");
+		puts ("\tmov cx, dx");
+		loadri (fn, NULL, &e->bin.r);
+
+		puts ("\tcmp bx, ax");
+		puts ("\tlahf");
+		puts ("\tmov bx, ax");
+		puts ("\tcmp cx, dx");
+		puts ("\tlahf");
+		puts ("\tand ah, bh");
+		goto common;
+
+	case DT_QWORD:
+		error ("TODO: EX_EQ and EX_NE for DT_QWORD");
+
+	case DT_FLOAT:
+	case DT_DOUBLE:
+	case DT_LDOUBLE:
+		error ("TODO: gen_eq(): floats");
+
+		assert (!e->bin.r.is_imm);
+		loadf (NULL, &fn->regs[e->bin.l]);
+		loadf ("fcomp", &fn->regs[e->bin.r.reg]);
+		puts ("\tfstsw ax");
+		if (ignore_nan) {
+			puts ("\tmov al, ah");
+			puts ("\tshr al, 3");
+			puts ("\tand al, 1");
+		} else {
+			l1 = nlbl++;
+			l2 = nlbl++;
+			puts ("\tand ah, 0b1101");
+			puts ("\tcmp ah, 0b1000");
+			printf ("\tjne .Li%d\n", l1);
+			printf ("\tmov al, 1\n");
+			printf ("\tjmp .Li%d\n\n", l2);
+			printf (".Li%d:\n", l1);
+			printf ("\txor al, al\n\n");
+			printf (".Li%d:\n", l2);
+		}
 		break;
+
+	common:
+		puts ("\tshl ah, 1");
+		puts ("\trol ax, 1");
+		puts ("\tand ax, 1");
+		if (inv)
+			puts ("\txor ax, 1");
+		break;
 	}
 	return 0;
 }
@@ -2245,10 +2329,10 @@ struct expr *e;
 		gen_div (fn, dt, e, 1);
 		break;
 	case EX_EQ:
-		gen_cmp (fn, e, "test", "e");
+		gen_eq (fn, e, 0);
 		break;
 	case EX_NE:
-		gen_cmp (fn, e, "test", "ne");
+		gen_eq (fn, e, 1);
 		break;
 	case EX_ULT:
 		gen_cmp (fn, e, "cmp", "b");
blob - 08dc0947bade90c0785e263d4809546f818db9ad
blob + 0fe93a079c3f055271efe5a78fd8ca5c157882fb
--- cc/irc/test.ir
+++ cc/irc/test.ir
@@ -210,7 +210,10 @@ fn cmp (): word {
 	let $0: word = 0;
 	let $1: word = 1;
 	let $2: word = eq $0, $1;
-	ret $2;
+	let $3: dword = 0;
+	let $4: dword = 1;
+	let $5: word = eq $3, $4;
+	ret $5;
 }
 
 fn fcmp (): word {
@@ -222,6 +225,7 @@ fn fcmp (): word {
 	let $5: word = fgt $0, $1;
 	let $6: word = fle $0, $1;
 	let $7: word = fge $0, $1;
+	# let $8: word = eq $0, $1;
 	nop;
 	ret 0;
 }