From 7170ac33135e6ecf89752d3949bcecf9b9766d1c Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Mon, 15 Jan 2018 13:01:37 -0800 Subject: [PATCH] tcg/arm: Fix double-word comparisons The code sequence we were generating was only good for unsigned comparisons. For signed comparisions, use the sequence from gcc. Fixes booting of ppc64 firmware, with a patch changing the code sequence for ppc comparisons. Tested-by: Michael Roth Reviewed-by: Peter Maydell Signed-off-by: Richard Henderson --- tcg/arm/tcg-target.inc.c | 86 +++++++++++++++++++++++++++++++++--------------- 1 file changed, 60 insertions(+), 26 deletions(-) diff --git a/tcg/arm/tcg-target.inc.c b/tcg/arm/tcg-target.inc.c index 98a12535a5..d7b09e8e0c 100644 --- a/tcg/arm/tcg-target.inc.c +++ b/tcg/arm/tcg-target.inc.c @@ -1103,6 +1103,56 @@ static inline void tcg_out_mb(TCGContext *s, TCGArg a0) } } +static TCGCond tcg_out_cmp2(TCGContext *s, const TCGArg *args, + const int *const_args) +{ + TCGReg al = args[0]; + TCGReg ah = args[1]; + TCGArg bl = args[2]; + TCGArg bh = args[3]; + TCGCond cond = args[4]; + int const_bl = const_args[2]; + int const_bh = const_args[3]; + + switch (cond) { + case TCG_COND_EQ: + case TCG_COND_NE: + case TCG_COND_LTU: + case TCG_COND_LEU: + case TCG_COND_GTU: + case TCG_COND_GEU: + /* We perform a conditional comparision. If the high half is + equal, then overwrite the flags with the comparison of the + low half. The resulting flags cover the whole. */ + tcg_out_dat_rI(s, COND_AL, ARITH_CMP, 0, ah, bh, const_bh); + tcg_out_dat_rI(s, COND_EQ, ARITH_CMP, 0, al, bl, const_bl); + return cond; + + case TCG_COND_LT: + case TCG_COND_GE: + /* We perform a double-word subtraction and examine the result. + We do not actually need the result of the subtract, so the + low part "subtract" is a compare. For the high half we have + no choice but to compute into a temporary. */ + tcg_out_dat_rI(s, COND_AL, ARITH_CMP, 0, al, bl, const_bl); + tcg_out_dat_rI(s, COND_AL, ARITH_SBC | TO_CPSR, + TCG_REG_TMP, ah, bh, const_bh); + return cond; + + case TCG_COND_LE: + case TCG_COND_GT: + /* Similar, but with swapped arguments, via reversed subtract. */ + tcg_out_dat_rI(s, COND_AL, ARITH_RSB | TO_CPSR, + TCG_REG_TMP, al, bl, const_bl); + tcg_out_dat_rI(s, COND_AL, ARITH_RSC | TO_CPSR, + TCG_REG_TMP, ah, bh, const_bh); + return tcg_swap_cond(cond); + + default: + g_assert_not_reached(); + } +} + #ifdef CONFIG_SOFTMMU #include "tcg-ldst.inc.c" @@ -1964,22 +2014,6 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode opc, tcg_out_goto_label(s, tcg_cond_to_arm_cond[args[2]], arg_label(args[3])); break; - case INDEX_op_brcond2_i32: - /* The resulting conditions are: - * TCG_COND_EQ --> a0 == a2 && a1 == a3, - * TCG_COND_NE --> (a0 != a2 && a1 == a3) || a1 != a3, - * TCG_COND_LT(U) --> (a0 < a2 && a1 == a3) || a1 < a3, - * TCG_COND_GE(U) --> (a0 >= a2 && a1 == a3) || (a1 >= a3 && a1 != a3), - * TCG_COND_LE(U) --> (a0 <= a2 && a1 == a3) || (a1 <= a3 && a1 != a3), - * TCG_COND_GT(U) --> (a0 > a2 && a1 == a3) || a1 > a3, - */ - tcg_out_dat_rIN(s, COND_AL, ARITH_CMP, ARITH_CMN, 0, - args[1], args[3], const_args[3]); - tcg_out_dat_rIN(s, COND_EQ, ARITH_CMP, ARITH_CMN, 0, - args[0], args[2], const_args[2]); - tcg_out_goto_label(s, tcg_cond_to_arm_cond[args[4]], - arg_label(args[5])); - break; case INDEX_op_setcond_i32: tcg_out_dat_rIN(s, COND_AL, ARITH_CMP, ARITH_CMN, 0, args[1], args[2], const_args[2]); @@ -1988,15 +2022,15 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode opc, tcg_out_dat_imm(s, tcg_cond_to_arm_cond[tcg_invert_cond(args[3])], ARITH_MOV, args[0], 0, 0); break; + + case INDEX_op_brcond2_i32: + c = tcg_out_cmp2(s, args, const_args); + tcg_out_goto_label(s, tcg_cond_to_arm_cond[c], arg_label(args[5])); + break; case INDEX_op_setcond2_i32: - /* See brcond2_i32 comment */ - tcg_out_dat_rIN(s, COND_AL, ARITH_CMP, ARITH_CMN, 0, - args[2], args[4], const_args[4]); - tcg_out_dat_rIN(s, COND_EQ, ARITH_CMP, ARITH_CMN, 0, - args[1], args[3], const_args[3]); - tcg_out_dat_imm(s, tcg_cond_to_arm_cond[args[5]], - ARITH_MOV, args[0], 0, 1); - tcg_out_dat_imm(s, tcg_cond_to_arm_cond[tcg_invert_cond(args[5])], + c = tcg_out_cmp2(s, args + 1, const_args + 1); + tcg_out_dat_imm(s, tcg_cond_to_arm_cond[c], ARITH_MOV, args[0], 0, 1); + tcg_out_dat_imm(s, tcg_cond_to_arm_cond[tcg_invert_cond(c)], ARITH_MOV, args[0], 0, 0); break; @@ -2093,9 +2127,9 @@ static const TCGTargetOpDef *tcg_target_op_def(TCGOpcode op) static const TCGTargetOpDef sub2 = { .args_ct_str = { "r", "r", "rI", "rI", "rIN", "rIK" } }; static const TCGTargetOpDef br2 - = { .args_ct_str = { "r", "r", "rIN", "rIN" } }; + = { .args_ct_str = { "r", "r", "rI", "rI" } }; static const TCGTargetOpDef setc2 - = { .args_ct_str = { "r", "r", "r", "rIN", "rIN" } }; + = { .args_ct_str = { "r", "r", "r", "rI", "rI" } }; switch (op) { case INDEX_op_goto_ptr: -- 2.11.4.GIT