/*
 * Acess2 ARM
 * - By John Hodge (thePowersGang)
 *
 * arch/arm7/proc.S
 * - Process management assembly
 */

#define PUSH_GPRS \
	str r0, [sp,#1*4];\
	str r1, [sp,#2*4];\
	str r2, [sp,#3*4];\
	str r3, [sp,#4*4];\
	str r4, [sp,#5*4];\
	str r5, [sp,#6*4];\
	str r6, [sp,#7*4];\
	str r7, [sp,#8*4];\
	str r8, [sp,#9*4];\
	str r9, [sp,#10*4];\
	str r10, [sp,#11*4];\
	str r11, [sp,#12*4];\
	str r12, [sp,#13*4];\
	str sp, [sp,#14*4];\
	str lr, [sp,#15*4];\
	sub sp, #16*4

#define POP_GPRS add sp, #16*4; \
	ldr r0, [sp,#1*4]; \
	ldr r1, [sp,#2*4]; \
	ldr r2, [sp,#3*4]; \
	ldr r3, [sp,#4*4]; \
	ldr r4, [sp,#5*4]; \
	ldr r5, [sp,#6*4]; \
	ldr r6, [sp,#7*4]; \
	ldr r7, [sp,#8*4]; \
	ldr r8, [sp,#9*4]; \
	ldr r9, [sp,#10*4]; \
	ldr r10, [sp,#11*4]; \
	ldr r11, [sp,#12*4]; \
	ldr r12, [sp,#13*4]; \
	ldr lr, [sp,#15*4];

.globl SwitchStacks
@ R0: New stack
@ R1: Pointer to where to save old stack
@ R2: New address space
SwitchStacks:
	PUSH_GPRS
	
	str sp, [r1]
	mov r0, sp
	
	@ Only update TTBR0 if the task has an explicit address space
	tst r2, r2
	mcrne p15, 0, r2, c2, c0, 0	@ Set TTBR0 to r2

	POP_GPRS
	bx lr