diff options
Diffstat (limited to 'kc/core/cpu/cpu_task.S')
| -rw-r--r-- | kc/core/cpu/cpu_task.S | 54 |
1 files changed, 0 insertions, 54 deletions
diff --git a/kc/core/cpu/cpu_task.S b/kc/core/cpu/cpu_task.S deleted file mode 100644 index a411028..0000000 --- a/kc/core/cpu/cpu_task.S +++ /dev/null @@ -1,54 +0,0 @@ -/* thread switching routines for x86_64 -* adapted from: -* https://wiki.osdev.org/Brendan%27s_Multi-tasking_Tutorial -* -* -*/ - -.hidden cpu_set_thread -.global cpu_set_thread -.type cpu_set_thread, @function -cpu_set_thread: - /* x86_64 SysV ABI - * must save the following registers to the stack: - * rbx, rsp, rbp, r12, r13, r14, r15 - * the following are the parameters for switching tasks - * rdi: pointer to control block of thread being switched to - * rsi: pointer to control block of the current thread - * rdx: pointer to this cpu's task state segment rsp0 field - */ - // test for attempt to switch to same thread - cmp %rdi,%rsi - je .Lnothing - // test for a NULL origin thread - test %rsi,%rsi - // skip saving the state for a NULL origin thread - jz .Lnull_thread - push %rbx - push %r12 - push %r13 - push %r14 - push %r15 - push %rbp - /* the current task will be in rsi */ - mov %rsp, 0(%rsi) // save the stack pointer for the current task -.Lnull_thread: - mov 0(%rdi),%rsp // new stack is the next's task's stack - mov 8(%rdi),%rbx // top of the next task's kernel stack - mov %rbx,0(%rdx) // save the esp0 to the tss - mov 16(%rdi),%rax // page map for the next task - mov %cr3, %rcx // in case we need to change the page map - cmp %rax,%rcx - je .Lfinish - mov %rax,%cr3 // if the page maps are not the same, reload -.Lfinish: - pop %rbp // get all the registers off the new task's stack - pop %r15 - pop %r14 - pop %r13 - pop %r12 - pop %rbx -.Lnothing: // do nothing if the threads are the same - ret // leave into the new task -.size cpu_set_thread, . - cpu_set_thread - |