platform/bios_ia32/bios_asm.S

39 	before. Clobbers %eax.
45 	movl	%cr0, %eax		// set the PE bit (0) to switch to protected mode
47 	movl	%eax, %cr0
61 	movl	SAVED_CR3, %eax	// restore the saved page directory
62 	orl		%eax, %eax		// is there a paging directory at all?
65 	movl	%eax, %cr3
67 	movl	%cr0, %eax		// set the PG bit (31) to enable paging
68 	orl		$0x80000000, %eax
69 	movl	%eax, %cr0
73 	movl	(%esp), %eax
74 	movl	%eax, REAL_MODE_STACK
77 	movl	SAVED_ESP, %eax
78 	movl	%eax, %esp
82 	movl	REAL_MODE_STACK, %eax
83 	movl	%eax, (%esp)
94 	Clobbers %eax.
98 	movl	%esp, %eax
99 	movl	%eax, SAVED_ESP
104 	movl	(%esp), %eax
105 	movl	%eax, REAL_MODE_STACK
108 	movl	%cr3, %eax			// save the page directory address
109 	movl	%eax, SAVED_CR3
111 	movl	%cr0, %eax
112 	andl	$0x7fffffff, %eax	// clear PG bit (31)
113 	movl	%eax, %cr0
115 	xor		%eax, %eax			// clear page directory to flush TLBs
116 	movl	%eax, %cr3
119 	movl	$REAL_MODE_STACK, %eax
120 	movl	%eax, %esp
121 	movl	%eax, %ebp
135 	movl	%cr0, %eax			// switch to real mode
137 	movl	%eax, %cr0
173 	movl	40(%esp), %eax
177 	// Since switch_to_real_mode() clobbers %eax, we have to handle
182 	movl	(%ebp), %eax
183 	movl	%eax, SAVED_EAX
196 	// restore %eax and %es from saved location
197 	movl	(SAVED_EAX - 0x10000), %eax
208 	// save %eax from the call
209 	movl	%eax, (SAVED_EAX - 0x10000)
220 	movl	44(%esp), %eax
222 	movl	%ebx, 4(%eax)
223 	movl	%ecx, 8(%eax)
224 	movl	%edx, 12(%eax)
225 	movl	%esi, 16(%eax)
226 	movl	%edi, 20(%eax)
227 	movl	SAVED_EAX, %ecx		// special handling for %eax and flags
228 	movl	%ecx, (%eax)
230 	movw	%cx, 26(%eax)
256 	xorl	%eax, %eax
275 	// save %eax
276 	movl	%eax, (SAVED_EAX - 0x10000)
284 	// restore %eax
285 	movl	SAVED_EAX, %eax