clear the carry flag before calling BIOS functions

include/BIOS/func/E820_memory_map.nasm

@@ -53,6 +53,7 @@ GetMemoryMap:
 .loop_L1:
     mov eax, 0x0000E820                     ; select 0xE820 function
     mov edx, 0x534D4150                     ; 'SMAP' magic
+    clc                                     ; clear carry
     int 0x15
     jc GetMemoryMap.error
     cmp eax, 0x534D4150

include/BIOS/func/a20enable.nasm

@@ -105,6 +105,7 @@ EnableA20:
     je EnableA20.endp         ; A20 is already enabled
 
     mov ax, 0x2403
+    clc                             ; clear carry
     int 0x15
     jc EnableA20.do_fallback_a20    ; carry = error...not supported?
     cmp ah, 0
@@ -121,6 +122,7 @@ EnableA20:
     ERROR STAGE2_A20_FAILED
 .do_bios_a20:
     mov ax, 0x2401
+    clc                             ; clear carry
     int 0x15
     jmp EnableA20.a20_check
 .do_fast_a20:

include/BIOS/func/ext_read.nasm

@@ -111,6 +111,7 @@ read_disk_raw:
     mov ah, 0x42                ; call #
     mov dl, byte [bp + 14]      ; drive #             
 
+    clc                         ; clear carry
     int 0x13
     jnc .endf