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updatedKernel2.asm
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updatedKernel2.asm
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;;; ; ================================================================================================================================
;;; ; kernel-stub.asm
;;; ; Conner Reilly / Tomal Hossain / Mohammed Ibrahim
;;; ;
;;; ; The assembly core that perform the basic initialization of the kernel, bootstrapping the installation of trap handlers and
;;; ; configuring the kernel's memory space.
;;; ;
;;; ; Revision 0 : 2010-09-06
;;; ; ================================================================================================================================
;;; ; ================================================================================================================================
.Code
;;; ; ================================================================================================================================
;;; ; ================================================================================================================================
;;; ; Entry point.
__start:
;;; Find RAM. Start the search at the beginning of the device table.
COPY %G0 *+_static_device_table_base
RAM_search_loop_top:
;;; End the search with failure if we've reached the end of the table without finding RAM.
BEQ +RAM_search_failure *%G0 *+_static_none_device_code
;;; If this entry is RAM, then end the loop successfully.
BEQ +RAM_found *%G0 *+_static_RAM_device_code
;;; This entry is not RAM, so advance to the next entry.
ADDUS %G0 %G0 *+_static_dt_entry_size ; %G0 = &dt[RAM]
JUMP +RAM_search_loop_top
RAM_search_failure:
;;; Record a code to indicate the error, and then halt.
COPY %G5 *+_static_kernel_error_RAM_not_found
HALT
RAM_found:
;;; RAM has been found. If it is big enough, create a stack.
ADDUS %G1 %G0 *+_static_dt_base_offset ; %G1 = &RAM[base]
COPY %G1 *%G1 ; %G1 = RAM[base]
ADDUS %G2 %G0 *+_static_dt_limit_offset ; %G2 = &RAM[limit]
COPY %G2 *%G2 ; %G2 = RAM[limit]
SUB %G0 %G2 %G1 ; %G0 = |RAM|
MULUS %G4 *+_static_min_RAM_KB *+_static_bytes_per_KB ; %G4 = |min_RAM|
BLT +RAM_too_small %G0 %G4
MULUS %G4 *+_static_kernel_KB_size *+_static_bytes_per_KB ; %G4 = |kmem|
ADDUS %SP %G1 %G4 ; %SP = kernel[base] + |kmem| = kernel[limit]
COPY %FP %SP ; Initialize %FP
;;; Copy the RAM and kernel bases and limits to statically allocated spaces.
COPY *+_static_RAM_base %G1
COPY *+_static_RAM_limit %G2
COPY *+_static_kernel_base %G1
COPY *+_static_kernel_limit %SP
;;; Set the base of the trap table.
SETTBR +tt_base
;; Set base of the interrupt buffer.
SETIBR +IB_IP
;;; ; initialize the trap table entries to point to the appropriate interrupt handlers
COPY *+BUS_ERROR +bus_err_int_handler
;;; ; it looks like right now on a CLOCK_ALARM, the simulator will vector to what I set for the PERMISSION_VIOLATION interrupt
COPY *+PERMISSION_VIOLATION +perm_int_handler
COPY *+CLOCK_ALARM +clock_int_handler
COPY *+SYSTEM_CALL +sysc_int_handler
COPY *+INVALID_INSTRUCTION +invinst_int_handler
;;; The kernel limit plus 1024 will become the base of the next program
ADDUS *+_static_mem_base *+_static_kernel_limit 1024
;;; With the stack initialized, call main() to begin booting proper.
SUBUS %SP %SP 12 ; Push pFP / ra / rv
COPY *%SP %FP ; pFP = %FP
COPY %FP %SP ; Update FP.
ADDUS %G5 %FP 4 ; %G5 = &ra
CALL +_procedure_main *%G5
;;; We should never be here, but wrap it up properly.
COPY %FP *%FP
ADDUS %SP %SP 12 ; Pop pFP / args[0] / ra / rv
COPY %G5 *+_static_kernel_error_main_returned
HALT
RAM_too_small:
;;; Set an error code and halt.
COPY %G5 *+_static_kernel_error_small_RAM
HALT
;;; ; ================================================================================================================================
;;; ; ================================================================================================================================
;;; ; Procedure: find_device
;;; ; Callee preserved registers:
;;; ; [%FP - 4]: G0
;;; ; [%FP - 8]: G1
;;; ; [%FP - 12]: G2
;;; ; [%FP - 16]: G4
;;; ; Parameters:
;;; ; [%FP + 0]: The device type to find.
;;; ; [%FP + 4]: The instance of the given device type to find (e.g., the 3rd ROM).
;;; ; Caller preserved registers:
;;; ; [%FP + 8]: FP
;;; ; Return address:
;;; ; [%FP + 12]
;;; ; Return value:
;;; ; [%FP + 16]: If found, a pointer to the correct device table entry; otherwise, null.
;;; ; Locals:
;;; ; %G0: The device type to find (taken from parameter for convenience).
;;; ; %G1: The instance of the given device type to find. (from parameter).
;;; ; %G2: The current pointer into the device table.
_procedure_find_device:
;;; Prologue: Preserve the registers used on the stack.
SUBUS %SP %SP 4
COPY *%SP %G0
SUBUS %SP %SP 4
COPY *%SP %G1
SUBUS %SP %SP 4
COPY *%SP %G2
SUBUS %SP %SP 4
COPY *%SP %G4
;;; Initialize the locals.
COPY %G0 *%FP
ADDUS %G1 %FP 4
COPY %G1 *%G1
COPY %G2 *+_static_device_table_base
find_device_loop_top:
;;; End the search with failure if we've reached the end of the table without finding the device.
BEQ +find_device_loop_failure *%G2 *+_static_none_device_code
;;; If this entry matches the device type we seek, then decrement the instance count. If the instance count hits zero, then
;;; the search ends successfully.
BNEQ +find_device_continue_loop *%G2 %G0
SUB %G1 %G1 1
BEQ +find_device_loop_success %G1 0
find_device_continue_loop:
;;; Advance to the next entry.
ADDUS %G2 %G2 *+_static_dt_entry_size
JUMP +find_device_loop_top
find_device_loop_failure:
;;; Set the return value to a null pointer.
ADDUS %G4 %FP 16 ; %G4 = &rv
COPY *%G4 0 ; rv = null
JUMP +find_device_return
find_device_loop_success:
;;; Set the return pointer into the device table that currently points to the given iteration of the given type.
ADDUS %G4 %FP 16 ; %G4 = &rv
COPY *%G4 %G2 ; rv = &dt[<device>]
;;; Fall through...
find_device_return:
;;; Epilogue: Restore preserved registers, then return.
COPY %G4 *%SP
ADDUS %SP %SP 4
COPY %G2 *%SP
ADDUS %SP %SP 4
COPY %G1 *%SP
ADDUS %SP %SP 4
COPY %G0 *%SP
ADDUS %SP %SP 4
ADDUS %G5 %FP 12 ; %G5 = &ra
JUMP *%G5
;;; ; ; ================================================================================================================================
;;; ; ; ================================================================================================================================
;;; ; ; Procedure: main
;;; ; ; Callee preserved registers:
;;; ; ; [%FP - 4]: G0
;;; ; ; [%FP - 8]: G3
;;; ; ; [%FP - 12]: G4
;;; ; ; Parameters:
;;; ; ; [%FP + 0]: A pointer to the beginning of a null-terminated string.
;;; ; ; Caller preserved registers:
;;; ; ; [%FP + 4]: FP
;;; ; ; Return address:
;;; ; ; [%FP + 8]
;;; ; ; Return value:
;;; ; ; <none>
;;; ; ; Locals:
;;; ; ; %G0: Pointer to the current position in the string.
_procedure_main:
JUMP +GET_ROM_COUNT
;;; ; Callee Prologue: Push preserved registers.
SUBUS %SP %SP 4
COPY *%SP %G0
SUBUS %SP %SP 4
COPY *%SP %G3
SUBUS %SP %SP 4
COPY *%SP %G4
;;; ; If not yet initialized, set the console base/limit statics.
;;; BNEQ +print_init_loop *+_static_console_base 0
SUBUS %SP %SP 12 ; Push pfp / ra / rv
COPY *%SP %FP ; pFP = %FP
SUBUS %SP %SP 4 ; Push arg[1]
COPY *%SP 3 ; Find the 3rd device of the given type (i.e. the init.vmx ROM).
SUBUS %SP %SP 4 ; Push arg[0]
COPY *%SP *+_static_ROM_device_code ; Find a ROM device.
COPY %FP %SP ; Update %FP
ADDUS %G5 %SP 12 ; %G5 = &ra
CALL +_CREATE *%G5 ; CREATE the init process
ADDUS %SP %SP 8 ; Pop arg[0,1]
COPY %FP *%SP ; %FP = pfp
ADDUS %SP %SP 8 ; Pop pfp / ra
COPY %G4 *%SP ; %G4 = &dt[init.vmx]
ADDUS %SP %SP 4 ; Pop rv
;;; ; Panic if the 3rd ROM (init.vmx file) was not found.
;;; BNEQ +main_found_3rd_ROM %G4 0
;;; COPY %G5 *+_static_kernel_error_ROM_not_found
;;; HALT
main_found_3rd_ROM:
;;; ADDUS %G3 %G4 *+_static_dt_base_offset %G3 = &static 3rd ROM[base]
;;; COPY *+_static_3rd_ROM_base *%G3 ; Store static 3rd ROM[base]
;;; ADDUS %G3 %G4 *+_static_dt_limit_offset ;%G3 = &static 3rd ROM[limit]
;;; COPY *+_static_3rd_ROM_limit *%G3 ; Store static 3rd ROM[limit]
;; Caller prologue for print.
SUBUS %SP %SP 8 ; Push pfp / ra (no return value)
COPY *%SP %FP ; pFP = %FP
SUBUS %SP %SP 4 ; Push arg[0]
COPY *%SP +_string_initializing_init ; Print out msg indicating we are jumping into init.
COPY %FP %SP ; Update %FP
ADDUS %G5 %SP 8 ; %G5 = &ra
CALL +_procedure_print *%G5 ; CALL print.
ADDUS %SP %SP 4 ; Pop arg[0]
COPY %FP *%SP ; %FP = pfp
ADDUS %SP %SP 8 ; Pop pfp / ra
JUMPMD *+p1_base 0b10
;;; Epilogue: Pop and restore preserved registers, and then return
;;; ; ================================================================================================================================
;;; ; Procedure: print
;;; ; Callee preserved registers:
;;; ; [%FP - 4]: G0
;;; ; [%FP - 8]: G3
;;; ; [%FP - 12]: G4
;;; ; Parameters:
;;; ; [%FP + 0]: A pointer to the beginning of a null-terminated string.
;;; ; Caller preserved registers:
;;; ; [%FP + 4]: FP
;;; ; Return address:
;;; ; [%FP + 8]
;;; ; Return value:
;;; ; <none>
;;; ; Locals:
;;; ; %G0: Pointer to the current position in the string.
_procedure_print:
;;; Prologue: Push preserved registers.
SUBUS %SP %SP 4
COPY *%SP %G0
SUBUS %SP %SP 4
COPY *%SP %G3
SUBUS %SP %SP 4
COPY *%SP %G4
;;; If not yet initialized, set the console base/limit statics.
BNEQ +print_init_loop *+_static_console_base 0
SUBUS %SP %SP 12 ; Push pfp / ra / rv
COPY *%SP %FP ; pFP = %FP
SUBUS %SP %SP 4 ; Push arg[1]
COPY *%SP 1 ; Find the 1st device of the given type.
SUBUS %SP %SP 4 ; Push arg[0]
COPY *%SP *+_static_console_device_code ; Find a console device.
COPY %FP %SP ; Update %FP
ADDUS %G5 %SP 12 ; %G5 = &ra
CALL +_procedure_find_device *%G5
ADDUS %SP %SP 8 ; Pop arg[0,1]
COPY %FP *%SP ; %FP = pfp
ADDUS %SP %SP 8 ; Pop pfp / ra
COPY %G4 *%SP ; %G4 = &dt[console]
ADDUS %SP %SP 4 ; Pop rv
;;; Panic if the console was not found.
BNEQ +print_found_console %G4 0
COPY %G5 *+_static_kernel_error_console_not_found
HALT
print_found_console:
ADDUS %G3 %G4 *+_static_dt_base_offset ; %G3 = &console[base]
COPY *+_static_console_base *%G3 ; Store static console[base]
ADDUS %G3 %G4 *+_static_dt_limit_offset ; %G3 = &console[limit]
COPY *+_static_console_limit *%G3 ; Store static console[limit]
print_init_loop:
;;; Loop through the characters of the given string until the null character is found.
COPY %G0 *%FP ; %G0 = str_ptr
print_loop_top:
COPYB %G4 *%G0 ; %G4 = current_char
;;; The loop should end if this is a null character
BEQ +print_loop_end %G4 0
;;; Scroll without copying the character if this is a newline.
COPY %G3 *+_static_newline_char ; %G3 = <newline>
BEQ +print_scroll_call %G4 %G3
;;; Assume that the cursor is in a valid location. Copy the current character into it.
;;; The cursor position c maps to buffer location: console[limit] - width + c
SUBUS %G3 *+_static_console_limit *+_static_console_width ; %G3 = console[limit] - width
ADDUS %G3 %G3 *+_static_cursor_column ; %G3 = console[limit] - width + c
COPYB *%G3 %G4 ; &(height - 1, c) = current_char
;;; Advance the cursor, scrolling if necessary.
ADD *+_static_cursor_column *+_static_cursor_column 1 ; c = c + 1
BLT +print_scroll_end *+_static_cursor_column *+_static_console_width ; Skip scrolling if c < width
;;; Fall through...
print_scroll_call:
SUBUS %SP %SP 8 ; Push pfp / ra
COPY *%SP %FP ; pfp = %FP
COPY %FP %SP ; %FP = %SP
ADDUS %G5 %FP 4 ; %G5 = &ra
CALL +_procedure_scroll_console *%G5
COPY %FP *%SP ; %FP = pfp
ADDUS %SP %SP 8 ; Pop pfp / ra
print_scroll_end:
;;; Place the cursor character in its new position.
SUBUS %G3 *+_static_console_limit *+_static_console_width ; %G3 = console[limit] - width
ADDUS %G3 %G3 *+_static_cursor_column ; %G3 = console[limit] - width + c
COPY %G4 *+_static_cursor_char ; %G4 = <cursor>
COPYB *%G3 %G4 ; console@cursor = <cursor>
;;; Iterate by advancing to the next character in the string.
ADDUS %G0 %G0 1
JUMP +print_loop_top
print_loop_end:
;;; Epilogue: Pop and restore preserved registers, then return.
COPY %G4 *%SP
ADDUS %SP %SP 4
COPY %G3 *%SP
ADDUS %SP %SP 4
COPY %G0 *%SP
ADDUS %SP %SP 4
ADDUS %G5 %FP 8 ; %G5 = &ra
JUMP *%G5
;;; ; ================================================================================================================================
;;; ; ================================================================================================================================
;;; ; Procedure: scroll_console
;;; ; Description: Scroll the console and reset the cursor at the 0th column.
;;; ; Callee reserved registers:
;;; ; [%FP - 4]: G0
;;; ; [%FP - 8]: G1
;;; ; [%FP - 12]: G4
;;; ; Parameters:
;;; ; <none>
;;; ; Caller preserved registers:
;;; ; [%FP + 0]: FP
;;; ; Return address:
;;; ; [%FP + 4]
;;; ; Return value:
;;; ; <none>
;;; ; Locals:
;;; ; %G0: The current destination address.
;;; ; %G1: The current source address.
_procedure_scroll_console:
;;; Prologue: Push preserved registers.
SUBUS %SP %SP 4
COPY *%SP %G0
SUBUS %SP %SP 4
COPY *%SP %G1
SUBUS %SP %SP 4
COPY *%SP %G4
;;; Initialize locals.
COPY %G0 *+_static_console_base ; %G0 = console[base]
ADDUS %G1 %G0 *+_static_console_width ; %G1 = console[base] + width
;;; Clear the cursor.
SUBUS %G4 *+_static_console_limit *+_static_console_width ; %G4 = console[limit] - width
ADDUS %G4 %G4 *+_static_cursor_column ; %G4 = console[limit] - width + c
COPYB *%G4 *+_static_space_char ; Clear cursor.
;;; Copy from the source to the destination.
;;; %G3 = DMA portal
;;; %G4 = DMA transfer length
ADDUS %G3 8 *+_static_device_table_base ; %G3 = &controller[limit]
SUBUS %G3 *%G3 12 ; %G3 = controller[limit] - 3*|word| = &DMA_portal
SUBUS %G4 *+_static_console_limit %G0 ; %G4 = console[base] - console[limit] = |console|
SUBUS %G4 %G4 *+_static_console_width ; %G4 = |console| - width
;;; Copy the source, destination, and length into the portal. The last step triggers the DMA copy.
COPY *%G3 %G1 ; DMA[source] = console[base] + width
ADDUS %G3 %G3 4 ; %G3 = &DMA[destination]
COPY *%G3 %G0 ; DMA[destination] = console[base]
ADDUS %G3 %G3 4 ; %G3 = &DMA[length]
COPY *%G3 %G4 ; DMA[length] = |console| - width; DMA trigger
;;; Perform a DMA transfer to blank the last line with spaces.
SUBUS %G3 %G3 8 ; %G3 = &DMA_portal
COPY *%G3 +_string_blank_line ; DMA[source] = &blank_line
ADDUS %G3 %G3 4 ; %G3 = &DMA[destination]
SUBUS *%G3 *+_static_console_limit *+_static_console_width ; DMA[destination] = console[limit] - width
ADDUS %G3 %G3 4 ; %G3 = &DMA[length]
COPY *%G3 *+_static_console_width ; DMA[length] = width; DMA trigger
;;; Reset the cursor position.
COPY *+_static_cursor_column 0 ; c = 0
SUBUS %G4 *+_static_console_limit *+_static_console_width ; %G4 = console[limit] - width
COPYB *%G4 *+_static_cursor_char ; Set cursor.
;;; Epilogue: Pop and restore preserved registers, then return.
COPY %G4 *%SP
ADDUS %SP %SP 4
COPY %G1 *%SP
ADDUS %SP %SP 4
COPY %G0 *%SP
ADDUS %SP %SP 4
ADDUS %G5 %FP 4 ; %G5 = &ra
JUMP *%G5
;;; ; ================================================================================================================================
;;; ; ; ================================================================================================================================
;;; ; ; Procedure: GET_ROM_COUNT
;;; ; ; Callee preserved registers:
;;; ; ; [%FP - 4]: G0
;;; ; ; [%FP - 8]: G1
;;; ; ; Parameters:
;;; ; ; None.
;;; ; ; Caller preserved registers:
;;; ; ; [%FP]: FP
;;; ; ; Return address:
;;; ; ; [%FP + 4]
;;; ; ; Return value:
;;; ; ; [%FP + 8]
;;; ; ; <number of ROMs>
;;; ; Locals:
;;; ; %G0: The current pointer into the device table.
;;; ; %G1: ROM count
GET_ROM_COUNT:
;;; Prologue: Preserve the registers used on the stack.
SUBUS %SP %SP 4
COPY *%SP %G0
SUBUS %SP %SP 4
COPY *%SP %G1
;;; Initialize the locals.
COPY %G0 *+_static_device_table_base ; Initialize %G0 to point to beginning of device table.
COPY %G1 0 ; No ROMs found yet.
GET_ROM_COUNT_loop_top:
;;; End the search if we've reached the end of the table without finding the device.
BEQ +GET_ROM_COUNT_loop_complete *%G0 *+_static_none_device_code
;;; If this entry matches the device type we seek, then increment the instance count.
BNEQ +GET_ROM_COUNT_continue_loop *%G0 *+_static_ROM_device_code
ADDUS %G1 %G1 1
GET_ROM_COUNT_continue_loop:
;;; Advance to the next entry.
ADDUS %G0 %G0 *+_static_dt_entry_size
JUMP +GET_ROM_COUNT_loop_top
GET_ROM_COUNT_loop_complete:
;;; Set the return value to the ROM count.
ADDUS %G0 %FP 8 ; %G0 = &rv
COPY *%G0 %G1 ; rv = ROM count
;;; Epilogue: Restore preserved registers, then return.
COPY %G1 *%SP
ADDUS %SP %SP 4
COPY %G0 *%SP
ADDUS %SP %SP 4
ADDUS %G5 %FP 4 ; %G5 = &ra
JUMP *%G5
;;; ; ; ================================================================================================================================
;;; ; ; ================================================================================================================================
;;; ; ; Procedure: _CREATE
;;; ; ; Callee preserved registers:
;;; ; ; [%FP - 4]: G0
;;; ; ; [%FP - 8]: G3
;;; ; ; [%FP - 12]: G4
;;; ; ; Parameters:
;;; ; ; [%FP + 0]: The device type to find...note that this is unnecessary, since we have ROM device in a static. I'll remove this arg if I have the time.
;;; ; ; [%FP + 4]: The instance of the given device type to find (e.g., the 3rd ROM).
;;; ; ; Caller preserved registers:
;;; ; ; [%FP + 8]: FP
;;; ; ; Return address:
;;; ; ; [%FP + 12]
;;; ; ; Return value:
;;; ; ; <pointer to the base of the loaded process in RAM>
;;; ; ; Locals:
;;; ; ; %G0: The ROM number that we want to load the process from.
_CREATE:
;;; ; the kernel needs to know how many processes have been created, because the way that I am implementing right now is that I am just creating all processes, and then starting the round robin scheduling algo. The reason that I'm doing this is because if I havent created all processes, and I try to schedule the next process, we will loop through the process table potentially looking for a process that hasnt been created yet
;;; ; Callee Prologue: Preserve registers
SUBUS %SP %SP 4
COPY *%SP %G0
SUBUS %SP %SP 4
COPY *%SP %G3
SUBUS %SP %SP 4
COPY *%SP %G4
;;; Initialize local
ADDUS %G0 %FP 4
COPY %G0 *%G0
;;; Caller Prologue to find device:
SUBUS %SP %SP 12 ; Push pfp / ra / rv
COPY *%SP %FP ; pFP = %FP
SUBUS %SP %SP 4 ; Push arg[1]
COPY *%SP %G0 ; %G0 contains the instance of the ROM device we want to find
SUBUS %SP %SP 4 ; Push arg[0]
COPY *%SP *+_static_ROM_device_code ; Find a ROM device.
COPY %FP %SP ; Update %FP
ADDUS %G5 %SP 12 ; %G5 = &ra
CALL +_procedure_find_device *%G5
ADDUS %SP %SP 8 ; Pop arg[0,1]
COPY %FP *%SP ; %FP = pfp
ADDUS %SP %SP 8 ; Pop pfp / ra
COPY %G4 *%SP ; %G4 = &dt[nth ROM]
ADDUS %SP %SP 4 ; Pop rv
;;; ; Panic if the ROM was not found.
BNEQ +_CREATE_found_ROM %G4 0
COPY %G5 *+_static_kernel_error_console_not_found
HALT
_CREATE_found_ROM:
ADDUS %G3 %G4 *+_static_dt_base_offset ; %G3 = &nthROM[base]
COPY %G0 *%G3 ; %G0 = ROM[base]
ADDUS %G3 %G4 *+_static_dt_limit_offset ; %G3 = &nthROM[limit]
COPY %G3 *%G3 ; %G3 = ROM[limit]
COPY %G4 *+_static_mem_base ; store base of the first free chunk of memory in %G4
_CREATE_copy_loop_top:
COPY *%G4 *%G0 ; copy the contents of the nth ROM into RAM, one word at a time
ADD %G0 %G0 4
ADD %G4 %G4 4
BEQ +_CREATE_copy_loop_end %G0 %G3 ; check to see if we have copied all contents from the ROM
JUMP +_CREATE_copy_loop_top
_CREATE_copy_loop_end:
;; The program has now been copied into RAM. Now, what we want is to CALL init_proc_entry(RAM[base], RAM[limit], process ID)
;; Caller prologue to init_proc_entry
SUBUS %SP %SP 8 ; Push pfp / ra (no return value)
COPY *%SP %FP ; pFP = %FP
SUBUS %SP %SP 4 ; Push arg[2]
ADDUS *%SP %FP 4 ; arg[2] = &ROM instance number
SUBUS %SP %SP 4 ; Push arg[1]
COPY *%SP %G4 ; arg[1] = RAM[limit] (limit = word after last word of prog)
SUBUS %SP %SP 4 ; Push arg[0]
COPY *%SP *+_static_mem_base ; arg[0] = RAM[base]
COPY %FP %SP ; Update %FP
ADDUS %G5 %SP 16 ; %G5 = &ra
CALL +_init_proc_entry *%G5 ; CALL init_proc_entry
ADDUS %SP %SP 12 ; Pop arg[0,1,2]
COPY %FP *%SP ; %FP = pfp
ADDUS %SP %SP 8 ; Pop pfp / ra
;;; We're done with function calls, so we're in the callee epilogue phase of the process. First I'm going to place the return value, because I need to change "_static_mem_base"
ADDUS %G3 %FP 16
COPY *%G3 *+_static_mem_base
;;; Now, change the value of "static_mem_base" for the next process to be created.
SUBUS %G4 %G4 *+_static_mem_base ; %G4 = ROM[length]
;; ADDUS %G5 %FP 16 ; %G5 = &rv
COPY *%G5 *+_static_mem_base ; the return value will be the base of the program in main memory
ADDUS *+_static_mem_base %G4 *+_static_mem_base ; get to limit of the program
ADDUS *+_static_mem_base *+_static_mem_base 1024 ; arbitrary buffer of 1024
;;; ; Epilogue: Pop and restore preserved registers, then return.
COPY %G4 *%SP
ADDUS %SP %SP 4
COPY %G3 *%SP
ADDUS %SP %SP 4
COPY %G0 *%SP
ADDUS %SP %SP 4
ADDUS %G5 %FP 12 ;%G5 = &ra
JUMP *%G5
JUMPMD *+_static_mem_base 0b10
;;; ; ; ================================================================================================================================
;;; ; ; ; ================================================================================================================================
;;; ; ; ; Procedure: _init_proc_entry
;;; ; ; ; Callee preserved registers:
;;; ; ; ; [%FP - 4]: G0
;;; ; ; ; [%FP - 8]: G3
;;; ; ; ; [%FP - 12]: G4
;;; ; ; ; Parameters:
;;; ; ; ; [%FP + 0]: RAM[base]
;;; ; ; ; [%FP + 4]: RAM[limit]
;;; ; ; ; [%FP + 8]: Process ID
;;; ; ; ; Caller preserved registers:
;;; ; ; ; [%FP + 12]: FP
;;; ; ; ; Return address:
;;; ; ; ; [%FP + 16]
;;; ; ; ; Return value:
;;; ; ; ; <none>
;;; ; ; ; Locals:
;;; ; ; ; %G0: RAM[base]
;;; ; ; ; %G2: address that we are at in process table
;;; ; ; ; %G3: RAM[limit]
;;; ; ; ; %G4: Process ID
_init_proc_entry:
;;; ; ; Callee Prologue: Preserve registers
SUBUS %SP %SP 4
COPY *%SP %G0
SUBUS %SP %SP 4
COPY *%SP %G2
SUBUS %SP %SP 4
COPY *%SP %G3
SUBUS %SP %SP 4
COPY *%SP %G4
;;; ; ; Initialize locals
;; Locals whose values are taken from the stack.
COPY %G0 *%FP ; %G0 = RAM[base]
ADDUS %G3 %FP 4
COPY %G3 *%G3 ; %G3 = RAM[limit]
ADDUS %G4 %FP 8
COPY %G4 *%G4 ; %G4 = &Process ID
COPY %G4 *%G4 ; %G4 = Process ID
;; BEQ +debugging_shit %G4 4
;; Other locals.
COPY %G2 +process_table
;;;
_find_proc_entry_loop_top:
;; Find the entry in the process table that we are looking for.
BEQ +_find_proc_entry_loop_end %G4 *%G2
ADDUS %G2 %G2 48
JUMP +_find_proc_entry_loop_end
_find_proc_entry_loop_end:
;; Now, set the base and limit variables for the process.
ADDUS %G2 %G2 4 ; %G2 = &process_table[base]
COPY *%G2 %G0 ; process_table[base] = RAM[base]
ADDUS %G2 %G2 4 ; %G2 = &process_table[limit]
COPY *%G2 %G3 ; process_table[limit] = RAM[limit]
;; We're done, let's clean up (restore registers) and return.
COPY %G4 *%SP
ADDUS %SP %SP 4
COPY %G3 *%SP
ADDUS %SP %SP 4
COPY %G2 *%SP
ADDUS %SP %SP 4
COPY %G0 *%SP
ADDUS %SP %SP 4
ADDUS %G5 %FP 16 ;%G5 = &ra
JUMP *%G5
debugging_shit:
JUMPMD %G0 0b10
;;; ; ; ================================================================================================================================
;; INTERRUPT HANDLERS
sysc_int_handler:
;;; ; ; Callee Prologue: Preserve registers
SUBUS %SP %SP 4
COPY *%SP %G0
SUBUS %SP %SP 4
COPY *%SP %G3
SUBUS %SP %SP 4
COPY *%SP %G4
;;; ; Caller Prologue to find device:
;;; ; If not yet initialized, set the console base/limit statics.
;;; ; BNEQ +print_init_loop *+_static_console_base 0
SUBUS %SP %SP 12 ; Push pfp / ra / rv
COPY *%SP %FP ; pFP = %FP
SUBUS %SP %SP 4 ; Push arg[1]
COPY *%SP %G0 ; we are assuming that we left the ROM that we want in %G0
SUBUS %SP %SP 4 ; Push arg[0]
COPY *%SP *+_static_ROM_device_code ; Find a ROM device.
COPY %FP %SP ; Update %FP
ADDUS %G5 %SP 12 ; %G5 = &ra
CALL +_CREATE *%G5
ADDUS %SP %SP 8 ; Pop arg[0,1]
COPY %FP *%SP ; %FP = pfp
ADDUS %SP %SP 8 ; Pop pfp / ra
COPY %G4 *%SP ; %G4 = RAM[base]
ADDUS %SP %SP 4 ; Pop rv
;; JUMPMD %G4 0b10
ADDUS *+IB_IP *+IB_IP 16
JUMPMD *+IB_IP 0b10
clock_int_handler:
COPY %G1 %G1
HALT
def_int_handler:
COPY %G2 %G2
HALT
invinst_int_handler:
COPY %G3 %G3
HALT
perm_int_handler:
COPY %G4 %G4
HALT
bus_err_int_handler:
COPY %G5 %G5
HALT
;;; ; ; ; ================================================================================================================================
;;; ; ; ; Procedure: _heap_allocator
;;; ; ; ; Callee preserved registers:
;;; ; ; ; [%FP - 4]: G0
;;; ; ; ; [%FP - 8]: G1
;;; ; ; ; Parameters:
;;; ; ; ; [%FP + 0]: size of memory chunk that we want to allocate
;;; ; ; ; Caller preserved registers:
;;; ; ; ; [%FP + 4]: FP
;;; ; ; ; Return address:
;;; ; ; ; [%FP + 8]
;;; ; ; ; Return value:
;;; ; ; ; [%FP + 12]
;;; ; ; ; <ptr to the base of the block we just allocated in the heap>
;;; ; ; ; Locals:
;;; ; ; ; %G0: size of memory chunk to allocate
;;; ; ; ; %G1: used to put rv on stack
;; How will we know if the heap is empty? *+_heap_top will have a value of zero
_heap_allocator:
;;; Callee prologue.
;;; ; ; Callee Prologue: Preserve registers
SUBUS %SP %SP 4
COPY *%SP %G0
SUBUS %SP %SP 4
COPY *%SP %G1
;;; ; ; Initialize locals
;; Locals whose values are taken from the stack.
COPY %G0 *%FP ; %G0 = size
;; if the heap hasn't been initialized, initialize it.
BNEQ +_allocate *+_heap_top 0
_initialize_heap:
;; to give an indicator that the heap is not empty, we will set _heap_top to 1
COPY *+_heap_top 0x1
;; since we are initializing the heap, we will make _heap_next_free_block equal the next block
ADDUS *+_heap_next_free_block +_heap_next_free_block 0x4
;;
_allocate:
;; All that we need to do is return the pointer to the next free block
ADDUS %G1 %FP 12 ; %G1 = &rv
COPY *%G1 *+_heap_next_free_block ; rv = &nextfreeblock
;; now we need to increase _heap_next_free_block by the size of the memory chunk asked for
ADDUS *+_heap_next_free_block *+_heap_next_free_block %G0
;; Callee epilogue: Restore registers and return
COPY %G1 *%SP
ADDUS %SP %SP 4
COPY %G0 *%SP
ADDUS %SP %SP 4
JUMP *%G5
;;; ; ================================================================================================================================
;;; ; ; ================================================================================================================================
;;; ; ; Procedure: _CREATE2 - this is the same as create, except im going to use the heap allocator to create the process table
;;; ; ; Callee preserved registers:
;;; ; ; [%FP - 4]: G0
;;; ; ; [%FP - 8]: G3
;;; ; ; [%FP - 12]: G4
;;; ; ; Parameters:
;;; ; ; [%FP + 0]: The device type to find...note that this is unnecessary, since we have ROM device in a static. I'll remove this arg if I have the time.
;;; ; ; [%FP + 4]: The instance of the given device type to find (e.g., the 3rd ROM).
;;; ; ; Caller preserved registers:
;;; ; ; [%FP + 8]: FP
;;; ; ; Return address:
;;; ; ; [%FP + 12]
;;; ; ; Return value:
;;; ; ; <pointer to the base of the loaded process in RAM>
;;; ; ; Locals:
;;; ; ; %G0: The ROM number that we want to load the process from.
_CREATE2:
;;; ; the kernel needs to know how many processes have been created, because the way that I am implementing right now is that I am just creating all processes, and then starting the round robin scheduling algo. The reason that I'm doing this is because if I havent created all processes, and I try to schedule the next process, we will loop through the process table potentially looking for a process that hasnt been created yet
;;; ; Callee Prologue: Preserve registers
SUBUS %SP %SP 4
COPY *%SP %G0
SUBUS %SP %SP 4
COPY *%SP %G3
SUBUS %SP %SP 4
COPY *%SP %G4
;;; Initialize local
ADDUS %G0 %FP 4
COPY %G0 *%G0
;;; Caller Prologue to find device:
SUBUS %SP %SP 12 ; Push pfp / ra / rv
COPY *%SP %FP ; pFP = %FP
SUBUS %SP %SP 4 ; Push arg[1]
COPY *%SP %G0 ; %G0 contains the instance of the ROM device we want to find
SUBUS %SP %SP 4 ; Push arg[0]
COPY *%SP *+_static_ROM_device_code ; Find a ROM device.
COPY %FP %SP ; Update %FP
ADDUS %G5 %SP 12 ; %G5 = &ra
CALL +_procedure_find_device *%G5
ADDUS %SP %SP 8 ; Pop arg[0,1]
COPY %FP *%SP ; %FP = pfp
ADDUS %SP %SP 8 ; Pop pfp / ra
COPY %G4 *%SP ; %G4 = &dt[nth ROM]
ADDUS %SP %SP 4 ; Pop rv
;;; ; Panic if the ROM was not found.
BNEQ +_CREATE2_found_ROM %G4 0
COPY %G5 *+_static_kernel_error_console_not_found
HALT
_CREATE2_found_ROM:
ADDUS %G3 %G4 *+_static_dt_base_offset ; %G3 = &nthROM[base]
COPY %G0 *%G3 ; %G0 = ROM[base]
ADDUS %G3 %G4 *+_static_dt_limit_offset ; %G3 = &nthROM[limit]
COPY %G3 *%G3 ; %G3 = ROM[limit]
COPY %G4 *+_static_mem_base ; store base of the first free chunk of memory in %G4
_CREATE2_copy_loop_top:
COPY *%G4 *%G0 ; copy the contents of the nth ROM into RAM, one word at a time
ADD %G0 %G0 4
ADD %G4 %G4 4
BEQ +_CREATE2_copy_loop_end %G0 %G3 ; check to see if we have copied all contents from the ROM
JUMP +_CREATE2_copy_loop_top
_CREATE2_copy_loop_end:
;; The program has now been copied into RAM. Now, what we want is to CALL init_proc_entry(RAM[base], RAM[limit], process ID)
;; Caller prologue to init_proc_entry
SUBUS %SP %SP 8 ; Push pfp / ra (no return value)
COPY *%SP %FP ; pFP = %FP
SUBUS %SP %SP 4 ; Push arg[2]
ADDUS *%SP %FP 4 ; arg[2] = &ROM instance number
SUBUS %SP %SP 4 ; Push arg[1]
COPY *%SP %G4 ; arg[1] = RAM[limit] (limit = word after last word of prog)
SUBUS %SP %SP 4 ; Push arg[0]
COPY *%SP *+_static_mem_base ; arg[0] = RAM[base]
COPY %FP %SP ; Update %FP
ADDUS %G5 %SP 16 ; %G5 = &ra
CALL +_init2_proc_entry *%G5 ; CALL init_proc_entry
ADDUS %SP %SP 12 ; Pop arg[0,1,2]
COPY %FP *%SP ; %FP = pfp
ADDUS %SP %SP 8 ; Pop pfp / ra
;;; We're done with function calls, so we're in the callee epilogue phase of the process. First I'm going to place the return value, because I need to change "_static_mem_base"
ADDUS %G3 %FP 16
COPY *%G3 *+_static_mem_base
;;; Now, change the value of "static_mem_base" for the next process to be created.
SUBUS %G4 %G4 *+_static_mem_base ; %G4 = ROM[length]
;; ADDUS %G5 %FP 16 ; %G5 = &rv
COPY *%G5 *+_static_mem_base ; the return value will be the base of the program in main memory
ADDUS *+_static_mem_base %G4 *+_static_mem_base ; get to limit of the program
ADDUS *+_static_mem_base *+_static_mem_base 1024 ; arbitrary buffer of 1024
;;; ; Epilogue: Pop and restore preserved registers, then return.
COPY %G4 *%SP
ADDUS %SP %SP 4
COPY %G3 *%SP
ADDUS %SP %SP 4
COPY %G0 *%SP
ADDUS %SP %SP 4
ADDUS %G5 %FP 12 ;%G5 = &ra
JUMP *%G5
;;; ; ; ; ================================================================================================================================
;;; ; ; ; Procedure: _init2_proc_entry (same as _init_proc_entry, but uses heap allocator)
;;; ; ; ; Callee preserved registers:
;;; ; ; ; [%FP - 4]: G0
;;; ; ; ; [%FP - 8]: G3
;;; ; ; ; [%FP - 12]: G4
;;; ; ; ; Parameters:
;;; ; ; ; [%FP + 0]: RAM[base]
;;; ; ; ; [%FP + 4]: RAM[limit]
;;; ; ; ; [%FP + 8]: Process ID
;;; ; ; ; Caller preserved registers:
;;; ; ; ; [%FP + 12]: FP
;;; ; ; ; Return address:
;;; ; ; ; [%FP + 16]
;;; ; ; ; Return value:
;;; ; ; ; <none>
;;; ; ; ; Locals:
;;; ; ; ; %G0: RAM[base]
;;; ; ; ; %G2: address that we are at in process table
;;; ; ; ; %G3: RAM[limit]
;;; ; ; ; %G4: Process ID
_init2_proc_entry:
;;; ; ; Callee Prologue: Preserve registers
SUBUS %SP %SP 4
COPY *%SP %G0
SUBUS %SP %SP 4
COPY *%SP %G2
SUBUS %SP %SP 4