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std::arch::global_asm! {
".text",
".global crash_context_getcontext",
".hidden crash_context_getcontext",
".type crash_context_getcontext, #function",
".align 0",
".fnstart",
"crash_context_getcontext:",
// First, save r4-r11
"add r1, r0, #(32 + 4 * 4)",
"stm r1, {{r4-r11}}",
// r12 is a scratch register, don't save it
// Save sp and lr explicitly.
// - sp can't be stored with stmia in Thumb-2
// - STM instructions that store sp and pc are deprecated in ARM
"str sp, [r0, #(32 + 13 * 4)]",
"str lr, [r0, #(32 + 14 * 4)]",
// Save the caller's address in 'pc'
"str lr, [r0, #(32 + 15 * 4)]",
// Save ucontext_t* pointer across next call
"mov r4, r0",
// Call sigprocmask(SIG_BLOCK, NULL, &(ucontext->uc_sigmask))
"mov r0, #0", // SIG_BLOCK
"mov r1, #0", // NULL
"add r2, r4, #104", // UCONTEXT_SIGMASK_OFFSET
"bl sigprocmask(PLT)",
/* Intentionally do not save the FPU state here. This is because on
* Linux/ARM, one should instead use ptrace(PTRACE_GETFPREGS) or
* ptrace(PTRACE_GETVFPREGS) to get it.
*
* Note that a real implementation of getcontext() would need to save
* this here to allow setcontext()/swapcontext() to work correctly.
*/
// Restore the values of r4 and lr
"mov r0, r4",
"ldr lr, [r0, #(32 + 14 * 4)]",
"ldr r4, [r0, #(32 + 4 * 4)]",
// Return 0
"mov r0, #0",
"bx lr",
".fnend",
".size crash_context_getcontext, . - crash_context_getcontext",
}