* grub-core/boot/i386/pc/startup_raw.S (grub_gate_a20): Remove

	argument. We don't disable Gate A20 in this code.

diff --git a/ChangeLog b/ChangeLog
index 7188f4e00b008851e57df5e11d78cb79c13d57c4..783b416a8a997c19396498c035aabe1ccc342457 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2013-10-25  Vladimir Serbinenko  <phcoder@gmail.com>
+
+       * grub-core/boot/i386/pc/startup_raw.S (grub_gate_a20): Remove
+       argument. We don't disable Gate A20 in this code.
+
 2013-10-25  Vladimir Serbinenko  <phcoder@gmail.com>
 
        * grub-core/boot/i386/qemu/boot.S: Ensure that A20 is enabled.

diff --git a/grub-core/boot/i386/pc/startup_raw.S b/grub-core/boot/i386/pc/startup_raw.S
index 06dec8c06bd350d572f7226572529b1daece2985..2796740303ea39892a8878f4a104f5f094c27f9f 100644 (file)
--- a/grub-core/boot/i386/pc/startup_raw.S
+++ b/grub-core/boot/i386/pc/startup_raw.S
@@ -100,7 +100,6 @@ LOCAL (codestart):
        /* The ".code32" directive takes GAS out of 16-bit mode. */
        .code32
 
-       incl    %eax
        cld
        call    grub_gate_a20
 
@@ -124,7 +123,7 @@ LOCAL (codestart):
        .text
 
 /*
- * grub_gate_a20(int on)
+ * grub_gate_a20(void)
  *
  * Gate address-line 20 for high memory.
  *
@@ -134,12 +133,10 @@ LOCAL (codestart):
  */
 
 grub_gate_a20: 
-       movl    %eax, %edx
-
 gate_a20_test_current_state:
        /* first of all, test if already in a good state */
        call    gate_a20_check_state
-       cmpb    %al, %dl
+       testb   %al, %al
        jnz     gate_a20_try_bios
        ret
 
@@ -149,18 +146,15 @@ gate_a20_try_bios:
        call    prot_to_real
 
        .code16
-       movw    $0x2400, %ax
-       testb   %dl, %dl
-       jz      1f
-       incw    %ax
-1:     int     $0x15
+       movw    $0x2401, %ax
+       int     $0x15
 
        DATA32  call    real_to_prot
        .code32
 
        popl    %ebp
        call    gate_a20_check_state
-       cmpb    %al, %dl
+       testb   %al, %al
        jnz     gate_a20_try_system_control_port_a
        ret
 
@@ -172,20 +166,13 @@ gate_a20_try_system_control_port_a:
        /* fourth, try the system control port A */
        inb     $0x92
        andb    $(~0x03), %al
-       testb   %dl, %dl
-       jz      6f
        orb     $0x02, %al
-6:     outb    $0x92
+       outb    $0x92
 
-       /* When turning off Gate A20, do not check the state strictly,
-          because a failure is not fatal usually, and Gate A20 is always
-          on some modern machines.  */
-       testb   %dl, %dl
-       jz      7f
        call    gate_a20_check_state
-       cmpb    %al, %dl
+       testb   %al, %al
        jnz     gate_a20_try_keyboard_controller
-7:     ret
+       ret
 
 gate_a20_flush_keyboard_buffer:
        inb     $0x64
@@ -211,11 +198,8 @@ gate_a20_try_keyboard_controller:
        andb    $0x02, %al
        jnz     4b
 
-       movb    $0xdd, %al
-       testb   %dl, %dl
-       jz      5f
-       orb     $0x02, %al
-5:     outb    $0x60
+       movb    $0xdf, %al
+       outb    $0x60
        call    gate_a20_flush_keyboard_buffer
 
        /* output a dummy command (USB keyboard hack) */
@@ -224,7 +208,7 @@ gate_a20_try_keyboard_controller:
        call    gate_a20_flush_keyboard_buffer
 
        call    gate_a20_check_state
-       cmpb    %al, %dl
+       testb   %al, %al
        /* everything failed, so restart from the beginning */
        jnz     gate_a20_try_bios
        ret
@@ -234,7 +218,7 @@ gate_a20_check_state:
        movl    $100, %ecx
 1:
        call    3f
-       cmpb    %al, %dl
+       testb   %al, %al
        jz      2f
        loop    1b
 2:
@@ -263,9 +247,8 @@ gate_a20_check_state:
        pushl   %ebx
        addl    $0x100000, %ebx
        movb    (%ebx), %ch
-       /* this result is 1 if A20 is on or 0 if it is off */
+       /* this result is 0 if A20 is on or 1 if it is off */
        subb    %ch, %al
-       xorb    $1, %al
        /* restore the original */
        popl    %ebx
        movb    %cl, (%ebx)