even more thingsHEADtrunk

1 files changed, 10 insertions, 3 deletions

diff --git a/cpu.ha b/cpu.ha
index 3ffea05..7c23714 100644
--- a/cpu.ha
+++ b/cpu.ha
@@ -110,15 +110,22 @@ fn mainloop(cpu: *cpu) void = {
 };
 
 export fn main() void = {
+	if (len(os::args) != 2)
+		fmt::fatalf("usage: {} FILE.r1b", os::args[0]);
+	const fname = os::args[1];
+
 	const cpu = cpu_new();
-	const fp = match (os::open("sys0.r1b")) {
+	const fp = match (os::open(fname)) {
 	case let i: io::file => yield i;
-	case let e: fs::error => fmt::fatalf("MISSING BOOT SECTOR: {}",
+	case let e: fs::error => fmt::fatalf("couldn't open boot sector {}",
 		fs::strerror(e));
 	};
 
 	match (io::readall(fp, cpu.mem[0x0200..0x0300])) {
-	case let e: io::error => fmt::fatalf("BOOT SECTOR READ ERROR: {}", io::strerror(e));
+	case let e: io::error => match (e) {
+		case io::underread => yield;
+		case let e: io::error => fmt::fatalf("couldn't read boot sector {}", io::strerror(e));
+	};
 	case => yield;
 	};