diff options
| -rw-r--r-- | src/arch/i386/transitions/librm.S | 21 |
1 files changed, 10 insertions, 11 deletions
diff --git a/src/arch/i386/transitions/librm.S b/src/arch/i386/transitions/librm.S index 9edbd4738..e916ba57b 100644 --- a/src/arch/i386/transitions/librm.S +++ b/src/arch/i386/transitions/librm.S @@ -455,28 +455,25 @@ prot_call: .code32 .globl real_call real_call: - /* Create register dump on PM stack */ + /* Create register dump and function pointer copy on PM stack */ pushal + pushl RC_OFFSET_FUNCTION(%esp) - /* Switch to real mode and move register dump to RM stack */ - movl $RC_OFFSET_END, %ecx + /* Switch to real mode and move register dump to RM stack */ + movl $( RC_OFFSET_RETADDR + 4 /* function pointer copy */ ), %ecx pushl $1f jmp prot_to_real .section ".text16" .code16 1: - /* Construct call to real-mode function */ - movw %sp, %bp - movw RC_OFFSET_FUNCTION(%bp), %ax - movw %ax, rc_function - /* Call real-mode function */ + popl rc_function popal call *rc_function pushal /* Switch to protected mode and move register dump back to PM stack */ - movl $RC_OFFSET_END, %ecx + movl $RC_OFFSET_RETADDR, %ecx pushl $1f jmp real_to_prot .section ".text" @@ -487,9 +484,11 @@ real_call: ret - /* Function vector, used because */ + /* Function vector, used because "call xx(%sp)" is not a valid + * 16-bit expression. + */ .section ".data16" -rc_function: .word 0 +rc_function: .word 0, 0 /**************************************************************************** * Stored real-mode and protected-mode stack pointers |