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| author | Freddie Chopin <freddie_chopin@op.pl> | 2010-11-13 15:42:00 +0100 |
|---|---|---|
| committer | Øyvind Harboe <oyvind.harboe@zylin.com> | 2010-11-15 09:17:14 +0100 |
| commit | 015bf559444edd9e7c524e951aad183fdaab9156 (patch) | |
| tree | f62886adff78bb89a803bca99c300703029a9641 /contrib | |
| parent | 6287c23b326cdebf20283b5c4eb8da4fae3eb821 (diff) | |
| download | openocd_libswd-015bf559444edd9e7c524e951aad183fdaab9156.tar.gz openocd_libswd-015bf559444edd9e7c524e951aad183fdaab9156.tar.bz2 openocd_libswd-015bf559444edd9e7c524e951aad183fdaab9156.tar.xz openocd_libswd-015bf559444edd9e7c524e951aad183fdaab9156.zip | |
Add comments and tiny improvements to STM32 flash loader algorithm
Add comments to assembly flash loader for STM32. Add tiny improvement in
size of the algorithm (40 vs 48 bytes) and tiny speed improvement (~1.5%,
as time is wasted on waiting for end of operation anyway).
Signed-off-by: Freddie Chopin <freddie_chopin@op.pl>
Diffstat (limited to 'contrib')
| -rw-r--r-- | contrib/loaders/flash/stm32x.s | 40 |
1 files changed, 22 insertions, 18 deletions
diff --git a/contrib/loaders/flash/stm32x.s b/contrib/loaders/flash/stm32x.s index dcf2b83c..6cf9f579 100644 --- a/contrib/loaders/flash/stm32x.s +++ b/contrib/loaders/flash/stm32x.s @@ -19,7 +19,10 @@ ***************************************************************************/ .text - .arm + .syntax unified + .thumb + .thumb_func + .global write /* r0 - source address @@ -27,26 +30,27 @@ r2 - count (halfword-16bit) r3 - result r4 - temp - r5 - temp */ +#define STM32_FLASH_CR_OFFSET 0x10 /* offset of CR register in FLASH struct */ +#define STM32_FLASH_SR_OFFSET 0x0c /* offset of CR register in FLASH struct */ + write: - ldr r4, STM32_FLASH_CR - ldr r5, STM32_FLASH_SR - mov r3, #1 - str r3, [r4, #0] - ldrh r3, [r0], #2 - strh r3, [r1], #2 + ldr r4, STM32_FLASH_BASE +write_half_word: + movs r3, #0x01 + str r3, [r4, #STM32_FLASH_CR_OFFSET] /* PG (bit0) == 1 => flash programming enabled */ + ldrh r3, [r0], #0x02 /* read one half-word from src, increment ptr */ + strh r3, [r1], #0x02 /* write one half-word from src, increment ptr */ busy: - ldr r3, [r5, #0] - tst r3, #0x01 - beq busy - tst r3, #0x14 - bne exit - subs r2, r2, #1 - bne write + ldr r3, [r4, #STM32_FLASH_SR_OFFSET] + tst r3, #0x01 /* BSY (bit0) == 1 => operation in progress */ + beq busy /* wait more... */ + tst r3, #0x14 /* PGERR (bit2) == 1 or WRPRTERR (bit4) == 1 => error */ + bne exit /* fail... */ + subs r2, r2, #0x01 /* decrement counter */ + bne write_half_word /* write next half-word if anything left */ exit: - bkpt #0 + bkpt #0x00 -STM32_FLASH_CR: .word 0x40022010 -STM32_FLASH_SR: .word 0x4002200C +STM32_FLASH_BASE: .word 0x40022000 /* base address of FLASH struct */ |