amd64/bareMetalOS-0.5.2/baremetal0.5.2/programs/smptest.asm

   1 ; SMP Test Program (v1.0, July 6 2010)
   2 ; Written by Ian Seyler
   3 ;
   4 ; BareMetal compile:
   5 ; nasm smptest.asm -o smptest.app
   6
   7
   8 [BITS 64]
   9 [ORG 0x0000000000200000]
  10
  11 %INCLUDE "bmdev.asm"
  12
  13 start:                          ; Start of program label
  14
  15         mov rax, ap_print_id    ; Our code to run on all CPUs
  16         xor rbx, rbx            ; Clear RBX as there is no argument
  17         mov rcx, 64             ; Number of instances to spawn
  18
  19 spawn:
  20         call b_smp_enqueue
  21         sub rcx, 1
  22         cmp rcx, 0
  23         jne spawn
  24
  25 bsp:
  26         call b_smp_dequeue      ; Try to dequeue a workload
  27         jc emptyqueue           ; If carry is set then the queue is empty
  28         call b_smp_run          ; Otherwise run the workload
  29         jne bsp                 ; If it is not empty try to do another workload
  30
  31 emptyqueue:
  32         call b_smp_wait         ; Wait for all other processors to finish
  33         call b_print_newline
  34
  35 ret                             ; Return to OS
  36
  37
  38 ; This procedure will be executed by each of the processors
  39 ; It requires mutually exclusive access while it creates the string and prints to the screen
  40 ; We must insure that only one CPU at a time can execute this code, so we employ a 'spinlock'.
  41 ap_print_id:
  42         mov rcx, 0x1FFFFF
  43 delay:
  44         dec rcx
  45         cmp rcx, 0
  46         jne delay
  47
  48 grablock:
  49         bt word [mutex], 0      ; Check if the mutex is free
  50         jnc grablock            ; If not check it again
  51
  52         lock                    ; The mutex was free, lock the bus
  53         btr word [mutex], 0     ; Try to grab the mutex
  54         jnc grablock            ; Jump if we were unsuccessful
  55
  56         call b_smp_get_id       ; Get the local APIC ID
  57         call b_debug_dump_al    ; Print the APIC ID
  58         mov al, ' '
  59         call b_print_char
  60
  61         bts word [mutex], 0     ; Release the mutex
  62 ret
  63
  64         mutex dw 1              ; The MUTual-EXclustion flag