correct some field sizes

include/BIOS/func/ext_read.nasm

@@ -98,13 +98,16 @@ read_disk_raw:
     mov ax, [bp + 12]
     mov word [bx + LBAPkt_t.xfer_size], ax
 
-    mov eax, [bp + 8]
+    mov eax, dword [bp + 8]
     mov dword [bx + LBAPkt_t.lower_lba], eax
 
+    ; upper_lba is zero from kmemset
+    ; TODO: possiblly support >32bit LBA addresses in the future, this limits us to 4GiB
+
     mov ax, [bp + 6]
     mov word [bx + LBAPkt_t.offset], ax
 
-    movzx ax, byte [bp + 4]
+    mov ax, [bp + 4]
     mov word [bx + LBAPkt_t.segment], ax
 
     xor ax, ax

include/util/kmem_func.nasm

@@ -21,18 +21,18 @@
 %ifndef __INC_KMEM_FUNC
 %include 'cdecl16.inc'
 
-; uint8_t* kmemset_byte(void* dst, uint8_t val, uint16_t len);
+; void* kmemset_byte(void* dst, uint8_t val, uint16_t len);
 ALIGN 4, db 0x90
 kmemset:
     __CDECL16_ENTRY
  .func:
-    mov     cx, [bp + 8]   ; size_t len
+    mov     cx, [bp + 8]        ; uint16_t len
-    mov     al, [bp + 6]   ; uint8_t val
+    mov     al, byte [bp + 6]   ; uint8_t val
     mov     di, [bp + 4]        ; void * dst
 
     cld
     rep     stosb
-    mov     ax, di         ; return pointer to dest
+    mov     ax, di         ; return pointer to dest + len (last elem of dest)
 .endp:
     __CDECL16_EXIT
     ret