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py/asmthumb: Add asm_thumb_ldrh_reg_reg_i12_optimised() helper func. 

Signed-off-by: Damien George <damien@micropython.org>
This commit is contained in:
Damien George 2022-05-20 14:30:09 +10:00
parent 689138d484
commit 94ae023136
2 changed files with 53 additions and 28 deletions
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80
py/asmthumb.c
View File

@ -55,6 +55,9 @@
#define OP_LDR_W_HI(reg_base) (0xf8d0 | (reg_base))
#define OP_LDR_W_LO(reg_dest, imm12) ((reg_dest) << 12 | (imm12))
#define OP_LDRH_W_HI(reg_base) (0xf8b0 | (reg_base))
#define OP_LDRH_W_LO(reg_dest, imm12) ((reg_dest) << 12 | (imm12))
#endif
static inline byte *asm_thumb_get_cur_to_write_bytes(asm_thumb_t *as, int n) {
@ -449,6 +452,35 @@ static inline void asm_thumb_ldr_reg_reg_i12(asm_thumb_t *as, uint reg_dest, uin
}
#endif
#if !MICROPY_EMIT_THUMB_ARMV7M
// emits code for: reg_dest = reg_base + offset << offset_shift
static void asm_thumb_add_reg_reg_offset(asm_thumb_t *as, uint reg_dest, uint reg_base, uint offset, uint offset_shift) {
if (reg_dest < ASM_THUMB_REG_R8 && reg_base < ASM_THUMB_REG_R8) {
if (offset << offset_shift < 256) {
if (reg_dest != reg_base) {
asm_thumb_mov_reg_reg(as, reg_dest, reg_base);
}
asm_thumb_add_rlo_i8(as, reg_dest, offset << offset_shift);
} else if (UNSIGNED_FIT8(offset) && reg_dest != reg_base) {
asm_thumb_mov_rlo_i8(as, reg_dest, offset);
asm_thumb_lsl_rlo_rlo_i5(as, reg_dest, reg_dest, offset_shift);
asm_thumb_add_rlo_rlo_rlo(as, reg_dest, reg_dest, reg_base);
} else if (reg_dest != reg_base) {
asm_thumb_mov_rlo_i16(as, reg_dest, offset << offset_shift);
asm_thumb_add_rlo_rlo_rlo(as, reg_dest, reg_dest, reg_dest);
} else {
uint reg_other = reg_dest ^ 7;
asm_thumb_op16(as, OP_PUSH_RLIST((1 << reg_other)));
asm_thumb_mov_rlo_i16(as, reg_other, offset << offset_shift);
asm_thumb_add_rlo_rlo_rlo(as, reg_dest, reg_dest, reg_other);
asm_thumb_op16(as, OP_POP_RLIST((1 << reg_other)));
}
} else {
assert(0); // should never be called for ARMV6M
}
}
#endif
void asm_thumb_ldr_reg_reg_i12_optimised(asm_thumb_t *as, uint reg_dest, uint reg_base, uint word_offset) {
if (reg_dest < ASM_THUMB_REG_R8 && reg_base < ASM_THUMB_REG_R8 && UNSIGNED_FIT5(word_offset)) {
asm_thumb_ldr_rlo_rlo_i5(as, reg_dest, reg_base, word_offset);
@ -456,39 +488,31 @@ void asm_thumb_ldr_reg_reg_i12_optimised(asm_thumb_t *as, uint reg_dest, uint re
#if MICROPY_EMIT_THUMB_ARMV7M
asm_thumb_ldr_reg_reg_i12(as, reg_dest, reg_base, word_offset);
#else
word_offset -= 31;
if (reg_dest < ASM_THUMB_REG_R8 && reg_base < ASM_THUMB_REG_R8) {
if (UNSIGNED_FIT8(word_offset) && (word_offset < 64 || reg_dest != reg_base)) {
if (word_offset < 64) {
if (reg_dest != reg_base) {
asm_thumb_mov_reg_reg(as, reg_dest, reg_base);
}
asm_thumb_add_rlo_i8(as, reg_dest, word_offset * 4);
} else {
asm_thumb_mov_rlo_i8(as, reg_dest, word_offset);
asm_thumb_lsl_rlo_rlo_i5(as, reg_dest, reg_dest, 2);
asm_thumb_add_rlo_rlo_rlo(as, reg_dest, reg_dest, reg_base);
}
} else {
if (reg_dest != reg_base) {
asm_thumb_mov_rlo_i16(as, reg_dest, word_offset * 4);
asm_thumb_add_rlo_rlo_rlo(as, reg_dest, reg_dest, reg_dest);
} else {
uint reg_other = reg_dest ^ 7;
asm_thumb_op16(as, OP_PUSH_RLIST((1 << reg_other)));
asm_thumb_mov_rlo_i16(as, reg_other, word_offset * 4);
asm_thumb_add_rlo_rlo_rlo(as, reg_dest, reg_dest, reg_other);
asm_thumb_op16(as, OP_POP_RLIST((1 << reg_other)));
}
}
} else {
assert(0); // should never be called for ARMV6M
}
asm_thumb_add_reg_reg_offset(as, reg_dest, reg_base, word_offset - 31, 2);
asm_thumb_ldr_rlo_rlo_i5(as, reg_dest, reg_dest, 31);
#endif
}
}
#if MICROPY_EMIT_THUMB_ARMV7M
static inline void asm_thumb_ldrh_reg_reg_i12(asm_thumb_t *as, uint reg_dest, uint reg_base, uint uint16_offset) {
asm_thumb_op32(as, OP_LDRH_W_HI(reg_base), OP_LDRH_W_LO(reg_dest, uint16_offset * 2));
}
#endif
void asm_thumb_ldrh_reg_reg_i12_optimised(asm_thumb_t *as, uint reg_dest, uint reg_base, uint uint16_offset) {
if (reg_dest < ASM_THUMB_REG_R8 && reg_base < ASM_THUMB_REG_R8 && UNSIGNED_FIT5(uint16_offset)) {
asm_thumb_ldrh_rlo_rlo_i5(as, reg_dest, reg_base, uint16_offset);
} else {
#if MICROPY_EMIT_THUMB_ARMV7M
asm_thumb_ldrh_reg_reg_i12(as, reg_dest, reg_base, uint16_offset);
#else
asm_thumb_add_reg_reg_offset(as, reg_dest, reg_base, uint16_offset - 31, 1);
asm_thumb_ldrh_rlo_rlo_i5(as, reg_dest, reg_dest, 31);
#endif
}
}
// this could be wrong, because it should have a range of +/- 16MiB...
#define OP_BW_HI(byte_offset) (0xf000 | (((byte_offset) >> 12) & 0x07ff))
#define OP_BW_LO(byte_offset) (0xb800 | (((byte_offset) >> 1) & 0x07ff))

1
py/asmthumb.h
View File

@ -328,6 +328,7 @@ void asm_thumb_mov_reg_local_addr(asm_thumb_t *as, uint rlo_dest, int local_num)
void asm_thumb_mov_reg_pcrel(asm_thumb_t *as, uint rlo_dest, uint label);
void asm_thumb_ldr_reg_reg_i12_optimised(asm_thumb_t *as, uint reg_dest, uint reg_base, uint word_offset); // convenience
void asm_thumb_ldrh_reg_reg_i12_optimised(asm_thumb_t *as, uint reg_dest, uint reg_base, uint uint16_offset); // convenience
void asm_thumb_b_label(asm_thumb_t *as, uint label); // convenience: picks narrow or wide branch
void asm_thumb_bcc_label(asm_thumb_t *as, int cc, uint label); // convenience: picks narrow or wide branch