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-rw-r--r--src/ast.c5
-rw-r--r--src/ast.h1
-rw-r--r--src/codegen.c49
-rw-r--r--tests/operators.c45
4 files changed, 89 insertions, 11 deletions
diff --git a/src/ast.c b/src/ast.c
index 4d30a66..0dcec0d 100644
--- a/src/ast.c
+++ b/src/ast.c
@@ -126,6 +126,11 @@ bool type_is_unsized(Type* ty) {
return ty->kind == TypeKind_void;
}
+bool type_is_unsigned(Type* ty) {
+ return ty->kind == TypeKind_uchar || ty->kind == TypeKind_ushort || ty->kind == TypeKind_uint ||
+ ty->kind == TypeKind_ulong || ty->kind == TypeKind_ullong || ty->kind == TypeKind_bool;
+}
+
int type_sizeof(Type* ty) {
if (type_is_unsized(ty)) {
fatal_error("type_sizeof: type size cannot be determined");
diff --git a/src/ast.h b/src/ast.h
index f12fd83..c6fd0e2 100644
--- a/src/ast.h
+++ b/src/ast.h
@@ -73,6 +73,7 @@ Type* type_new_static_string(int len);
Type* type_array_to_ptr(Type* ty);
Type* type_new_func(Type* result, AstNode* params);
bool type_is_unsized(Type* ty);
+bool type_is_unsigned(Type* ty);
int type_sizeof_struct(Type* ty);
int type_sizeof_union(Type* ty);
diff --git a/src/codegen.c b/src/codegen.c
index 2da6851..10a0287 100644
--- a/src/codegen.c
+++ b/src/codegen.c
@@ -205,11 +205,21 @@ static void codegen_binary_expr(CodeGen* g, BinaryExprNode* expr, GenMode gen_mo
} else if (expr->op == TokenKind_star) {
fprintf(g->out, " imul rax, rdi\n");
} else if (expr->op == TokenKind_slash) {
- fprintf(g->out, " cqo\n");
- fprintf(g->out, " idiv rdi\n");
+ if (type_is_unsigned(expr->lhs->ty)) {
+ fprintf(g->out, " xor rdx, rdx\n");
+ fprintf(g->out, " div rdi\n");
+ } else {
+ fprintf(g->out, " cqo\n");
+ fprintf(g->out, " idiv rdi\n");
+ }
} else if (expr->op == TokenKind_percent) {
- fprintf(g->out, " cqo\n");
- fprintf(g->out, " idiv rdi\n");
+ if (type_is_unsigned(expr->lhs->ty)) {
+ fprintf(g->out, " xor rdx, rdx\n");
+ fprintf(g->out, " div rdi\n");
+ } else {
+ fprintf(g->out, " cqo\n");
+ fprintf(g->out, " idiv rdi\n");
+ }
fprintf(g->out, " mov rax, rdx\n");
} else if (expr->op == TokenKind_and) {
fprintf(g->out, " and rax, rdi\n");
@@ -221,9 +231,12 @@ static void codegen_binary_expr(CodeGen* g, BinaryExprNode* expr, GenMode gen_mo
fprintf(g->out, " mov rcx, rdi\n");
fprintf(g->out, " shl rax, cl\n");
} else if (expr->op == TokenKind_rshift) {
- // TODO: check if the operand is signed or unsigned
fprintf(g->out, " mov rcx, rdi\n");
- fprintf(g->out, " sar rax, cl\n");
+ if (type_is_unsigned(expr->lhs->ty)) {
+ fprintf(g->out, " shr rax, cl\n");
+ } else {
+ fprintf(g->out, " sar rax, cl\n");
+ }
} else if (expr->op == TokenKind_eq) {
fprintf(g->out, " cmp rax, rdi\n");
fprintf(g->out, " sete al\n");
@@ -274,11 +287,21 @@ static void codegen_assign_expr_helper(CodeGen* g, AssignExprNode* expr) {
} else if (expr->op == TokenKind_assign_mul) {
fprintf(g->out, " imul rax, rdi\n");
} else if (expr->op == TokenKind_assign_div) {
- fprintf(g->out, " cqo\n");
- fprintf(g->out, " idiv rdi\n");
+ if (type_is_unsigned(expr->lhs->ty)) {
+ fprintf(g->out, " xor rdx, rdx\n");
+ fprintf(g->out, " div rdi\n");
+ } else {
+ fprintf(g->out, " cqo\n");
+ fprintf(g->out, " idiv rdi\n");
+ }
} else if (expr->op == TokenKind_assign_mod) {
- fprintf(g->out, " cqo\n");
- fprintf(g->out, " idiv rdi\n");
+ if (type_is_unsigned(expr->lhs->ty)) {
+ fprintf(g->out, " xor rdx, rdx\n");
+ fprintf(g->out, " div rdi\n");
+ } else {
+ fprintf(g->out, " cqo\n");
+ fprintf(g->out, " idiv rdi\n");
+ }
fprintf(g->out, " mov rax, rdx\n");
} else if (expr->op == TokenKind_assign_or) {
fprintf(g->out, " or rax, rdi\n");
@@ -291,7 +314,11 @@ static void codegen_assign_expr_helper(CodeGen* g, AssignExprNode* expr) {
fprintf(g->out, " shl rax, cl\n");
} else if (expr->op == TokenKind_assign_rshift) {
fprintf(g->out, " mov rcx, rdi\n");
- fprintf(g->out, " sar rax, cl\n");
+ if (type_is_unsigned(expr->lhs->ty)) {
+ fprintf(g->out, " shr rax, cl\n");
+ } else {
+ fprintf(g->out, " sar rax, cl\n");
+ }
} else {
unreachable();
}
diff --git a/tests/operators.c b/tests/operators.c
index e089477..5d969f2 100644
--- a/tests/operators.c
+++ b/tests/operators.c
@@ -116,6 +116,51 @@ int main() {
k >>= 3;
ASSERT_EQ(8, k);
+ // unsigned division / modulo
+ // (unsigned long)-1 = 0xFFFFFFFFFFFFFFFF
+ // 0xFFFFFFFFFFFFFFFF / 9 = 0x1C71C71C71C71C71 (huge positive)
+ // 0xFFFFFFFFFFFFFFFF % 9 = 6
+ // signed: -1 / 9 == 0 and -1 % 9 == -1
+ unsigned long u_max = -1L;
+ ASSERT_EQ(6L, u_max % 9);
+ ASSERT_EQ(1L, u_max % 7);
+ ASSERT_EQ(0, u_max / 9 == 0);
+ ASSERT_EQ(u_max, (u_max / 9) * 9 + u_max % 9);
+
+ long s_neg = -1L;
+ ASSERT_EQ(0L, s_neg / 9);
+ ASSERT_EQ(-1L, s_neg % 9);
+
+ // unsigned right shift (logical, fills 0)
+ // 0xFFFFFFFFFFFFFFFF >> 1 = 0x7FFFFFFFFFFFFFFF
+ unsigned long highbit = 1L;
+ for (int p = 0; p < 63; p += 1)
+ highbit *= 2; // 0x8000000000000000
+ unsigned long lmax = highbit - 1; // 0x7FFFFFFFFFFFFFFF
+ ASSERT_EQ(lmax, ((unsigned long)-1L) >> 1);
+
+ // signed right shift (arithmetic, preserves sign)
+ long s_neg2 = -1L;
+ ASSERT_EQ(-1L, s_neg2 >> 1);
+ ASSERT_EQ(-2L, (-8L) >> 2);
+
+ // compound assignment
+ unsigned long u_div = -1L;
+ u_div /= 9;
+ ASSERT_EQ(0, u_div == 0);
+
+ unsigned long u_mod = -1L;
+ u_mod %= 9;
+ ASSERT_EQ(6L, u_mod);
+
+ unsigned long u_shr = -1L;
+ u_shr >>= 1;
+ ASSERT_EQ(lmax, u_shr);
+
+ long s_shr = -1L;
+ s_shr >>= 1;
+ ASSERT_EQ(-1L, s_shr);
+
// ternary operator
ASSERT_EQ(2, 1 ? 2 : 3);
ASSERT_EQ(5, 0 ? 4 : 5);
generated by cgit v1.3.1 (git 2.54.0) at 2026-06-01 18:18:52 +0000