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py/asmrv32: Make lt/le comparisons emitter shorter.

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This commit simplifies the emitter code in charge of generating opcodes
performing less-than and less-than-or-equal comparisons.

By rewriting the SLT/SLTU opcode generator (handling less-than
comparisons) and de-inlining the less-than comparison generator call in
the less-than-or-equal generator, the output binary is ~80 bytes smaller
(measurements taken from the QEMU port).

Signed-off-by: Alessandro Gatti <a.gatti@frob.it>
This commit is contained in:
Alessandro Gatti 2025-07-10 00:50:15 +02:00 committed by Damien George
parent b1d5c656de
commit 0ee3f99da2
1 changed files with 3 additions and 11 deletions
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14
py/asmrv32.c
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@ -573,12 +573,8 @@ void asm_rv32_meta_comparison_ne(asm_rv32_t *state, mp_uint_t rs1, mp_uint_t rs2
}
void asm_rv32_meta_comparison_lt(asm_rv32_t *state, mp_uint_t rs1, mp_uint_t rs2, mp_uint_t rd, bool unsigned_comparison) {
// slt(u) rd, rs1, rs2
if (unsigned_comparison) {
asm_rv32_opcode_sltu(state, rd, rs1, rs2);
} else {
asm_rv32_opcode_slt(state, rd, rs1, rs2);
}
// slt|sltu rd, rs1, rs2
asm_rv32_emit_word_opcode(state, RV32_ENCODE_TYPE_R(0x33, (0x02 | (unsigned_comparison ? 1 : 0)), 0x00, rd, rs1, rs2));
}
void asm_rv32_meta_comparison_le(asm_rv32_t *state, mp_uint_t rs1, mp_uint_t rs2, mp_uint_t rd, bool unsigned_comparison) {
@ -588,11 +584,7 @@ void asm_rv32_meta_comparison_le(asm_rv32_t *state, mp_uint_t rs1, mp_uint_t rs2
// ... ; PC + 8
asm_rv32_opcode_cli(state, rd, 1);
asm_rv32_opcode_beq(state, rs1, rs2, 8);
if (unsigned_comparison) {
asm_rv32_opcode_sltu(state, rd, rs1, rs2);
} else {
asm_rv32_opcode_slt(state, rd, rs1, rs2);
}
asm_rv32_meta_comparison_lt(state, rs1, rs2, rd, unsigned_comparison);
}
#endif // MICROPY_EMIT_RV32