1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/contextSwitch.s	Mon May 30 18:28:41 2011 +0200
     1.3 @@ -0,0 +1,128 @@
     1.4 +#include "VMS.h"
     1.5 +
     1.6 +.data
     1.7 +
     1.8 +
     1.9 +.text
    1.10 +
    1.11 +//Save return label address for the coreLoop to pointer
    1.12 +//Arguments: Pointer to variable holding address
    1.13 +.globl saveCoreLoopReturnAddr
    1.14 +saveCoreLoopReturnAddr:
    1.15 +    movl    0x4(%esp) , %eax       #load pointer
    1.16 +    movl    $coreLoopReturn, %ecx   #load label address
    1.17 +    movl    %ecx, (%eax)           #save address
    1.18 +    ret
    1.19 +
    1.20 +
    1.21 +
    1.22 +//Switches form CoreLoop to VP ether normal VP or the Master Loop
    1.23 +//switch to virt procr's stack and frame ptr then jump to virt procr fn
    1.24 +/* VirtProcr  offsets:
    1.25 + * 0xc  stackPtr
    1.26 + * 0x10 framePtr
    1.27 + * 0x14 nextInstrPt
    1.28 + * 0x1c coreLoopFramePtr
    1.29 + * 0x20 coreLoopStackPtr
    1.30 + *
    1.31 + * _VMSMasterEnv  offsets:
    1.32 + * 0x24 coreLoopStartPt
    1.33 + * 0x28 coreLoopEndPt
    1.34 + * 0x30 masterLock
    1.35 + */
    1.36 +.globl switchToVP
    1.37 +switchToVP:
    1.38 +    movl    0x4(%esp) , %ecx         #get VirtProcr
    1.39 +    movl    %esp      , 0x20(%ecx)   #save core loop stack pointer 
    1.40 +    movl    %ebp      , 0x1c(%ecx)   #save core loop frame pointer
    1.41 +    movl    0x0c(%ecx), %esp         #restore stack pointer
    1.42 +    movl    0x10(%ecx), %ebp         #restore frame pointer
    1.43 +    movl    0x14(%ecx), %eax         #get jmp pointer
    1.44 +    jmp     *%eax                    #jmp to VP
    1.45 +coreLoopReturn:
    1.46 +    ret
    1.47 +
    1.48 +    
    1.49 +//switches to core loop. saves return address
    1.50 +/* VirtProcr  offsets:
    1.51 + * 0xc  stackPtr
    1.52 + * 0x10 framePtr
    1.53 + * 0x14 nextInstrPt
    1.54 + * 0x1c coreLoopFramePtr
    1.55 + * 0x20 coreLoopStackPtr
    1.56 + *
    1.57 + * _VMSMasterEnv  offsets:
    1.58 + * 0x24 coreLoopStartPt
    1.59 + * 0x28 coreLoopEndPt
    1.60 + * 0x30 masterLock
    1.61 + */
    1.62 +.globl switchToCoreLoop
    1.63 +switchToCoreLoop:
    1.64 +    movl    0x4(%esp) , %ecx         #get VirtProcr
    1.65 +    movl    $VPReturn , 0x14(%ecx)   #store return address
    1.66 +    movl    %esp      , 0x0c(%ecx)   #save stack pointer 
    1.67 +    movl    %ebp      , 0x10(%ecx)   #save frame pointer
    1.68 +    movl    0x20(%ecx), %esp         #restore stack pointer
    1.69 +    movl    0x1c(%ecx), %ebp         #restore frame pointer
    1.70 +    movl    $_VMSMasterEnv, %ecx
    1.71 +    movl    (%ecx)    , %ecx
    1.72 +    movl    0x24(%ecx), %eax         #get CoreLoopStartPt
    1.73 +    jmp     *%eax                    #jmp to CoreLoop
    1.74 +VPReturn:
    1.75 +    ret
    1.76 +
    1.77 +
    1.78 +
    1.79 +//switches to core loop from master. saves return address
    1.80 +/* VirtProcr  offsets:
    1.81 + * 0xc  stackPtr
    1.82 + * 0x10 framePtr
    1.83 + * 0x14 nextInstrPt
    1.84 + * 0x1c coreLoopFramePtr
    1.85 + * 0x20 coreLoopStackPtr
    1.86 + *
    1.87 + * _VMSMasterEnv  offsets:
    1.88 + * 0x24 coreLoopStartPt
    1.89 + * 0x28 coreLoopEndPt
    1.90 + * 0x30 masterLock
    1.91 + */
    1.92 +.globl masterSwitchToCoreLoop
    1.93 +masterSwitchToCoreLoop:
    1.94 +    movl    0x4(%esp) , %ecx         #get VirtProcr
    1.95 +    movl    $MasterReturn, 0x14(%ecx)   #store return address
    1.96 +    movl    %esp      , 0x0c(%ecx)   #save stack pointer 
    1.97 +    movl    %ebp      , 0x10(%ecx)   #save frame pointer
    1.98 +    movl    0x20(%ecx), %esp         #restore stack pointer
    1.99 +    movl    0x1c(%ecx), %ebp         #restore frame pointer
   1.100 +    movl    $_VMSMasterEnv, %ecx
   1.101 +    movl    (%ecx)    , %ecx
   1.102 +    movl    0x24(%ecx), %eax         #get CoreLoopStartPt
   1.103 +    movl    $0x0      , 0x30(%ecx)   #release lock
   1.104 +    jmp     *%eax                    #jmp to CoreLoop
   1.105 +MasterReturn:
   1.106 +    ret
   1.107 +
   1.108 +
   1.109 +//Switch to terminateCoreLoop
   1.110 +//no need to call because the stack is already set up for switchVP
   1.111 +//do not save register of VP because this function will never return
   1.112 +/* VirtProcr  offsets:
   1.113 + * 0xc  stackPtr
   1.114 + * 0x10 framePtr
   1.115 + * 0x14 nextInstrPt
   1.116 + * 0x1c coreLoopFramePtr
   1.117 + * 0x20 coreLoopStackPtr
   1.118 + *
   1.119 + * _VMSMasterEnv  offsets:
   1.120 + * 0x24 coreLoopStartPt
   1.121 + * 0x28 coreLoopEndPt
   1.122 + * 0x30 masterLock
   1.123 + */
   1.124 +.globl asmTerminateCoreLoop
   1.125 +asmTerminateCoreLoop:
   1.126 +    movl    0x4(%esp) , %ecx         #get VirtProcr
   1.127 +    movl    0x20(%ecx), %esp         #restore stack pointer
   1.128 +    movl    0x1c(%ecx), %ebp         #restore frame pointer
   1.129 +    movl    $terminateCoreLoop, %eax
   1.130 +    jmp     *%eax                    #jmp to CoreLoop 
   1.131 +