uaccess.S asm comments

a5a12d68 · Silas Boyd-Wickizer · e5609838 · a5a12d68
--- a/kernel/uaccess.S
+++ b/kernel/uaccess.S
@@ -4,11 +4,15 @@
 .code64
 .globl __fetchstr
 .align 8
+// rdi kernel dst
+// rsi user src
+// rdx kernel len
+// We aren't allowed to touch rbx,rsp,rbp,r12-r15
 __fetchstr:
        mov     %gs:0x8, %r11
        movl    $1, PROC_UACCESS(%r11)

-        // %rcx is loop instruction index
+        // %rcx is loop instruction counter
        mov     %rdx, %rcx
        xor     %rax, %rax
 1: