syscall: Turn uprint() into proper console write

1 files changed, 8 insertions, 6 deletions

diff --git a/src/lib/syscall.zig b/src/lib/syscall.zig
index d15810b..dcf246a 100644
--- a/src/lib/syscall.zig
+++ b/src/lib/syscall.zig
@@ -4,6 +4,7 @@
 
 const std = @import("std");
 
+const Console = @import("Console.zig");
 const instructions = @import("instructions.zig");
 const mem = @import("mem.zig");
 const paging = @import("paging.zig");
@@ -59,9 +60,10 @@ fn errorName(trap_frame: *const trap.Frame) !usize {
     return n;
 }
 
-// uprint(str_addr: usize, len: usize) void
-fn uprint(trap_frame: *const trap.Frame) void {
+// uprint(bytes_addr: usize, len: usize) !usize
+fn uprint(trap_frame: *const trap.Frame) !usize {
     const vaddr = trap_frame.general_purpose_registers[10];
+    const len = trap_frame.general_purpose_registers[11];
 
     const procmem: *paging.Table = @ptrFromInt(instructions.satp.read().ppn << 12);
     const paddr = procmem.translate(vaddr) orelse {
@@ -70,11 +72,11 @@ fn uprint(trap_frame: *const trap.Frame) void {
         unreachable;
     };
 
-    const str_ptr: [*]const u8 = @ptrFromInt(paddr);
-    const str = str_ptr[0..trap_frame.general_purpose_registers[11]];
+    const bytes_ptr: [*]const u8 = @ptrFromInt(paddr);
+    const bytes = bytes_ptr[0..len];
 
-    const w = @import("Console.zig").autoChoose().?.writer();
-    w.print("User message: {s}\r\n", .{str}) catch unreachable;
+    const w = Console.autoChoose().?.writer();
+    return w.write(bytes);
 }
 
 // launch(bytes: [*]align(@alignOf(std.elf.Elf64_Ehdr)) const u8, len: usize) !usize