mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-04-23 09:05:31 +00:00
Code Activity

Fixed renormalization in fp.fma. Relates to #872.

Browse source
This commit is contained in:
Christoph M. Wintersteiger 2017-07-28 23:01:01 +01:00
parent e677030b74
commit 175f042db8
2 changed files with 27 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

17
src/ast/fpa/fpa2bv_converter.cpp
View file

@ -1672,6 +1672,22 @@ void fpa2bv_converter::mk_fma(func_decl * f, unsigned num, expr * const * args,
extra_is_zero = m.mk_eq(extra, m_bv_util.mk_numeral(0, 2));
dbg_decouple("fpa2bv_fma_extra", extra);
res_exp = m.mk_ite(extra_is_zero, e_exp, m_bv_util.mk_bv_add(e_exp, m_bv_util.mk_numeral(1, ebits + 2)));
// Renormalize
expr_ref zero_e2(m), min_exp(m), sig_lz(m), max_exp_delta(m), sig_lz_capped(m), renorm_delta(m);
zero_e2 = m_bv_util.mk_numeral(0, ebits + 2);
mk_min_exp(ebits+2, min_exp);
mk_leading_zeros(sig_abs, ebits+2, sig_lz);
sig_lz = m_bv_util.mk_bv_sub(sig_lz, m_bv_util.mk_numeral(2, ebits+2));
max_exp_delta = m_bv_util.mk_bv_sub(res_exp, min_exp);
sig_lz_capped = m.mk_ite(m_bv_util.mk_sle(sig_lz, max_exp_delta), sig_lz, max_exp_delta);
renorm_delta = m.mk_ite(m_bv_util.mk_sle(zero_e2, sig_lz_capped), sig_lz_capped, zero_e2);
res_exp = m_bv_util.mk_bv_sub(res_exp, renorm_delta);
sig_abs = m_bv_util.mk_bv_shl(sig_abs, m_bv_util.mk_zero_extend(2*sbits-ebits, renorm_delta));
dbg_decouple("fpa2bv_fma_sig_lz", sig_lz);
dbg_decouple("fpa2bv_fma_renorm_delta", renorm_delta);
unsigned too_short = 0;
if (sbits < 5) {
too_short = 6 - sbits + 1;
@ -1705,7 +1721,6 @@ void fpa2bv_converter::mk_fma(func_decl * f, unsigned num, expr * const * args,
SASSERT(m_bv_util.get_bv_size(res_sig_2) == sbits + 4);
res_sig = m.mk_ite(extra_is_zero, res_sig_1, res_sig_2);
res_exp = m.mk_ite(extra_is_zero, e_exp, m_bv_util.mk_bv_add(e_exp, m_bv_util.mk_numeral(1, ebits + 2)));
dbg_decouple("fpa2bv_fma_res_sig", res_sig);
dbg_decouple("fpa2bv_fma_res_exp", res_exp);