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asmarm: Fix bug with encoding small negative ints using MVN instruction.

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This commit is contained in:
Paul Sokolovsky 2014-12-14 03:24:17 +02:00
parent 83d27b0f0b
commit c0bc3bd736
3 changed files with 16 additions and 2 deletions
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5
py/asmarm.c
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@ -282,8 +282,9 @@ void asm_arm_mov_reg_i32(asm_arm_t *as, uint rd, int imm) {
// TODO: There are more variants of immediate values
if ((imm & 0xFF) == imm) {
emit_al(as, asm_arm_op_mov_imm(rd, imm));
} else if (imm < 0 && ((-imm) & 0xFF) == -imm) {
emit_al(as, asm_arm_op_mvn_imm(rd, -imm));
} else if (imm < 0 && imm >= -256) {
// mvn is "move not", not "move negative"
emit_al(as, asm_arm_op_mvn_imm(rd, ~imm));
} else {
//Insert immediate into code and jump over it
emit_al(as, 0x59f0000 | (rd << 12)); // ldr rd, [pc]

9
tests/micropython/viper_binop_comp_imm.py Normal file
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@ -0,0 +1,9 @@
# comparisons with immediate boundary values
@micropython.viper
def f(a: int):
print(a == -1, a == -255, a == -256, a == -257)
f(-1)
f(-255)
f(-256)
f(-257)

4
tests/micropython/viper_binop_comp_imm.py.exp Normal file
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@ -0,0 +1,4 @@
True False False False
False True False False
False False True False
False False False True