TonBERRY/micropython
3
0
Fork 0
Code Pull Requests Activity

py/asm*: Support assembling code to jump to a register, and get PC+off.

Browse Source 
Useful for position independent code, and implementing state machines.
This commit is contained in:
Damien George
2018-08-16 13:45:24 +10:00
parent f7d6108d1a
commit 2964b41c28
10 changed files with 122 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
py/asmarm.c
View File

@@ -273,6 +273,21 @@ void asm_arm_mov_reg_local_addr(asm_arm_t *as, uint rd, int local_num) {
emit_al(as, asm_arm_op_add_imm(rd, ASM_ARM_REG_SP, local_num << 2));
}
void asm_arm_mov_reg_pcrel(asm_arm_t *as, uint reg_dest, uint label) {
assert(label < as->base.max_num_labels);
mp_uint_t dest = as->base.label_offsets[label];
mp_int_t rel = dest - as->base.code_offset;
rel -= 12 + 8; // adjust for load of rel, and then PC+8 prefetch of add_reg_reg_reg
// To load rel int reg_dest, insert immediate into code and jump over it
emit_al(as, 0x59f0000 | (reg_dest << 12)); // ldr rd, [pc]
emit_al(as, 0xa000000); // b pc
emit(as, rel);
// Do reg_dest += PC
asm_arm_add_reg_reg_reg(as, reg_dest, reg_dest, ASM_ARM_REG_PC);
}
void asm_arm_lsl_reg_reg(asm_arm_t *as, uint rd, uint rs) {
// mov rd, rd, lsl rs
emit_al(as, 0x1a00010 | (rd << 12) | (rs << 8) | rd);
@@ -362,4 +377,8 @@ void asm_arm_bl_ind(asm_arm_t *as, void *fun_ptr, uint fun_id, uint reg_temp) {
emit(as, (uint) fun_ptr);
}
void asm_arm_bx_reg(asm_arm_t *as, uint reg_src) {
emit_al(as, 0x012fff10 | reg_src);
}
#endif // MICROPY_EMIT_ARM