diff options
Diffstat (limited to 'src/app')
| -rw-r--r-- | src/app/transactiontest/util.S | 108 |
1 files changed, 65 insertions, 43 deletions
diff --git a/src/app/transactiontest/util.S b/src/app/transactiontest/util.S index 76988e3..1a12736 100644 --- a/src/app/transactiontest/util.S +++ b/src/app/transactiontest/util.S @@ -5,15 +5,18 @@ #define SRAM_BASE #1c00h #define SRAM_SIZE 4096 -; SRAM backup space -sram_backup: +; SRAM and stack pointer backup space +sp_backup1: + .space 2 +sram_backup1: .space SRAM_SIZE - -; Stack Pointer backup -sp_backup: +sp_backup2: .space 2 +sram_backup2: + .space SRAM_SIZE -; Backup Cookie: Do we have valid data or has the FRAM been wiped? +; Backup Cookie: Do we have valid data (and if yes, where?) +; or has the FRAM been wiped? backup_cookie: .space 2 @@ -27,35 +30,40 @@ asm_save_all: push r\reg .endr - ; We will soon have valid data - mov #1234h, r10 - mov r10, &backup_cookie + mov &backup_cookie, r10 ; content of backup_cookie -> r10 + mov #sp_backup1, r11 ; address of sp_backup1 -> r11 + cmp r10, r11 ; backup_cookie == addr. of sp_backup1? + jne do_save_all ; if not, the previous backup went to space 2 or never happened -> write backup to space 1 + ; otherwise, the previous backup went to space 1 -> write backup to space 2 - mov r1, &sp_backup + mov #sp_backup2, r11 - mov SRAM_BASE, r10 - mov #sram_backup, r11 - - ; Interrupts may alter global variables in SRAM and thus lead to inconsistencies +do_save_all: dint + mov r1, 0(r11) ; store stack pointer in sp_backup(1|2) + mov r11, r9 ; backup location -> r9 + mov SRAM_BASE, r10 ; SRAM area start -> r10 save_sram_word: - mov @r10+, 0(r11) add #2, r11 + mov @r10+, 0(r11) cmp SRAM_BASE+SRAM_SIZE, r10 jlo save_sram_word + mov r9, &backup_cookie ; save backup location (addr. of sp_backup(1|2)) in backup_cookie + eint ; revert changes to callee-saved registers pop r11 pop r10 + pop r9 ; remove unchanged registers from stack - add #12, r1 + add #10, r1 ret -; load entire SRAM and CPU register stat from persistent FRAM, +; load entire SRAM and CPU register state from persistent FRAM, ; if it contains valid backup data. Execution will resume at the ; last place where asm_save_all() was called is if nothing in between ; had happened. Does not take possible the state of hardware peripherals @@ -64,31 +72,37 @@ asm_load_all: ; check if we have backup data push r11 - mov &backup_cookie, r11 - cmp #1234h, r11 + push r10 + mov &backup_cookie, r10 - ; yes? -> load it + ; ... in location 1? + mov #sp_backup1, r11 + cmp r10, r11 + jeq do_load_all + + ; ... in location 2? + mov #sp_backup2, r11 + cmp r10, r11 jeq do_load_all ; no? -> too bad, resume with normal startup + pop r10 pop r11 ret - dint - do_load_all: + dint + ; restore stack pointer + mov @r11, r1 + add #2, r11 ; restore SRAM from backup - mov #sram_backup, r10 - mov SRAM_BASE, r11 + mov SRAM_BASE, r10 load_sram_word: - mov @r10+, 0(r11) - add #2, r11 - cmp SRAM_BASE+SRAM_SIZE, r11 + mov @r11+, 0(r10) + add #2, r10 + cmp SRAM_BASE+SRAM_SIZE, r10 jlo load_sram_word - ; restore stack pointer - mov &sp_backup, r1 - ; restore registers .irp reg,11,10,9,8,7,6,5,4 pop r\reg @@ -104,30 +118,38 @@ load_sram_word: ; Stack and CPU registers are left as-is, the program flow is not altered. asm_load_mem: + ; check if we have backup data push r11 - mov &backup_cookie, r11 - cmp #1234h, r11 + push r10 + mov &backup_cookie, r10 + + ; ... in location 1? + mov #sp_backup1, r11 + cmp r10, r11 + jeq do_load_mem + + ; ... in location 2? + mov #sp_backup2, r11 + cmp r10, r11 jeq do_load_mem + + ; no? -> too bad, resume with normal startup + pop r10 pop r11 ret - dint - do_load_mem: - push r10 - push r9 + dint ; restore SRAM from backup, excluding stack ; -> everything from SRAM start (inclusive) to @sp (exclusive). Reminder: SP == R1 on MSP430 - mov r1, r9 - mov #sram_backup, r10 - mov SRAM_BASE, r11 -load_sram_word2: - mov @r10+, 0(r11) add #2, r11 - cmp r9, r11 + mov SRAM_BASE, r10 +load_sram_word2: + mov @r11+, 0(r10) + add #2, r10 + cmp r1, r10 jlo load_sram_word2 - pop r9 pop r10 pop r11 |