syscall: Provide HWI devices by kind

Closes #59.

1 files changed, 20 insertions, 0 deletions

diff --git a/src/lib/syscall.zig b/src/lib/syscall.zig
index 8d42e7a..b618979 100644
--- a/src/lib/syscall.zig
+++ b/src/lib/syscall.zig
@@ -5,6 +5,7 @@
 const std = @import("std");
 const Console = @import("Console.zig");
 const TrapFrame = @import("TrapFrame.zig");
+const hwinfo = @import("hwinfo.zig");
 const mem = @import("mem.zig");
 const paging = @import("paging.zig");
 const process = @import("process.zig");
@@ -29,6 +30,7 @@ pub fn handler(proc: *process.Info, trap_frame: *TrapFrame) !void {
         100005 => trap_frame.setReturnValue(processId(proc)),
         100006 => trap_frame.setReturnValue(threadId(proc)),
         100007 => trap_frame.setReturnValue(rawUserinit(trap_frame)),
+        100008 => trap_frame.setReturnValue(devicesByKind(trap_frame)),
         else => return HandleError.UnknownSyscall,
     }
 }
@@ -147,3 +149,21 @@ fn rawUserinit(trap_frame: *const TrapFrame) usize {
     ptr.* = userinit.tarball;
     return userinit.tarball.len;
 }
+
+// devicesByKind(kind: hwinfo.DevKind, devices: [*]hwinfo.Dev, len: usize) !usize
+fn devicesByKind(trap_frame: *const TrapFrame) !usize {
+    const kind: hwinfo.DevKind = @enumFromInt(trap_frame.general_purpose_registers[10]);
+    const devices: [*]hwinfo.Dev = @ptrFromInt(trap_frame.general_purpose_registers[11]);
+    const len = trap_frame.general_purpose_registers[12];
+
+    var i: usize = 0;
+    var devs = try hwinfo.byKind(kind);
+    while (try devs.next()) |dev| {
+        if (i >= len) break;
+
+        devices[i] = dev;
+        i += 1;
+    }
+
+    return i;
+}