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py: Fix stack access in thumb native emitter.

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This commit is contained in:
Damien George
2014-05-07 23:27:45 +01:00
parent be6aa53cdb
commit d509ac25f9
6 changed files with 58 additions and 20 deletions
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24
py/asmthumb.c
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@@ -166,15 +166,29 @@ STATIC void asm_thumb_write_word32(asm_thumb_t *as, int w32) {
#define OP_ADD_SP(num_words) (0xb000 | (num_words))
#define OP_SUB_SP(num_words) (0xb080 | (num_words))
// locals:
// - stored on the stack in ascending order
// - numbered 0 through as->num_locals-1
// - SP points to first local
//
// | SP
// v
// l0 l1 l2 ... l(n-1)
// ^ ^
// | low address | high address in RAM
void asm_thumb_entry(asm_thumb_t *as, int num_locals) {
// work out what to push and how many extra space to reserve on stack
// work out what to push and how many extra spaces to reserve on stack
// so that we have enough for all locals and it's aligned an 8-byte boundary
// we push extra regs (r1, r2, r3) to help do the stack adjustment
// we probably should just always subtract from sp, since this would be more efficient
// for push rlist, lowest numbered register at the lowest address
uint reglist;
uint stack_adjust;
if (num_locals < 0) {
num_locals = 0;
}
// don't ppop r0 because it's used for return value
// don't pop r0 because it's used for return value
switch (num_locals) {
case 0:
reglist = 0xf2;
@@ -398,14 +412,14 @@ void asm_thumb_mov_reg_i32_aligned(asm_thumb_t *as, uint reg_dest, int i32) {
void asm_thumb_mov_local_reg(asm_thumb_t *as, int local_num, uint rlo_src) {
assert(rlo_src < REG_R8);
int word_offset = as->num_locals - local_num - 1;
int word_offset = local_num;
assert(as->pass < ASM_THUMB_PASS_EMIT || word_offset >= 0);
asm_thumb_op16(as, OP_STR_TO_SP_OFFSET(rlo_src, word_offset));
}
void asm_thumb_mov_reg_local(asm_thumb_t *as, uint rlo_dest, int local_num) {
assert(rlo_dest < REG_R8);
int word_offset = as->num_locals - local_num - 1;
int word_offset = local_num;
assert(as->pass < ASM_THUMB_PASS_EMIT || word_offset >= 0);
asm_thumb_op16(as, OP_LDR_FROM_SP_OFFSET(rlo_dest, word_offset));
}
@@ -414,7 +428,7 @@ void asm_thumb_mov_reg_local(asm_thumb_t *as, uint rlo_dest, int local_num) {
void asm_thumb_mov_reg_local_addr(asm_thumb_t *as, uint rlo_dest, int local_num) {
assert(rlo_dest < REG_R8);
int word_offset = as->num_locals - local_num - 1;
int word_offset = local_num;
assert(as->pass < ASM_THUMB_PASS_EMIT || word_offset >= 0);
asm_thumb_op16(as, OP_ADD_REG_SP_OFFSET(rlo_dest, word_offset));
}