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Move TaskContext into TCB instead of kstack.

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This commit is contained in:
Yifan Wu 2021-07-10 12:35:17 +08:00
parent f1aabb5e0e
commit 92b949a01f
6 changed files with 49 additions and 46 deletions
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27
os/src/task/switch.S
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@ -1,37 +1,34 @@
.altmacro
.macro SAVE_SN n
sd s\n, (\n+1)*8(sp)
sd s\n, (\n+2)*8(a0)
.endm
.macro LOAD_SN n
ld s\n, (\n+1)*8(sp)
ld s\n, (\n+2)*8(a1)
.endm
.section .text
.globl __switch
__switch:
# __switch(
# current_task_cx_ptr2: &*const TaskContext,
# next_task_cx_ptr2: &*const TaskContext
# current_task_cx_ptr: *mut TaskContext,
# next_task_cx_ptr: *const TaskContext
# )
# push TaskContext to current sp and save its address to where a0 points to
addi sp, sp, -13*8
sd sp, 0(a0)
# fill TaskContext with ra & s0-s11
sd ra, 0(sp)
# save kernel stack of current task
sd sp, 8(a0)
# save ra & s0~s11 of current execution
sd ra, 0(a0)
.set n, 0
.rept 12
SAVE_SN %n
.set n, n + 1
.endr
# ready for loading TaskContext a1 points to
ld sp, 0(a1)
# load registers in the TaskContext
ld ra, 0(sp)
# restore ra & s0~s11 of next execution
ld ra, 0(a1)
.set n, 0
.rept 12
LOAD_SN %n
.set n, n + 1
.endr
# pop TaskContext
addi sp, sp, 13*8
# restore kernel stack of next task
ld sp, 8(a1)
ret