* [Qemu-devel] [PATCH] SPARC target : Fix carry flag update in addxcc and subxcc ops @ 2006-04-08 13:46 Even Rouault 2006-04-09 20:38 ` Paul Brook 2006-04-10 17:57 ` [Qemu-devel] [PATCH] SPARC target : Fix carry flag update in addxccand subxc Blue Swirl 0 siblings, 2 replies; 7+ messages in thread From: Even Rouault @ 2006-04-08 13:46 UTC (permalink / raw) To: qemu-devel [-- Attachment #1: Type: text/plain, Size: 270 bytes --] I send a patch that should fix a bug in the update of carry flag for addxcc and subxcc instructions when the carry flag is set before the evaluation of the instruction. (the fix is identical to what is done in the similar instruction op_adcl_T0_T1_cc for arm target) [-- Attachment #2: qemu-sparc-carry-xcc-ops.patch --] [-- Type: text/x-diff, Size: 2130 bytes --] ? patch-qemu-sparc-xcc_ops.txt Index: op.c =================================================================== RCS file: /sources/qemu/qemu/target-sparc/op.c,v retrieving revision 1.18 diff -u -p -r1.18 op.c --- op.c 30 Oct 2005 17:28:50 -0000 1.18 +++ op.c 7 Apr 2006 22:04:40 -0000 @@ -415,9 +415,9 @@ void OPPROTO op_addx_T1_T0(void) void OPPROTO op_addx_T1_T0_cc(void) { target_ulong src1; - + target_ulong has_carry = FLAG_SET(PSR_CARRY); src1 = T0; - T0 += T1 + FLAG_SET(PSR_CARRY); + T0 += T1 + has_carry; env->psr = 0; #ifdef TARGET_SPARC64 if (!(T0 & 0xffffffff)) @@ -435,7 +435,7 @@ void OPPROTO op_addx_T1_T0_cc(void) env->xcc |= PSR_ZERO; if ((int64_t) T0 < 0) env->xcc |= PSR_NEG; - if (T0 < src1) + if (T0 < src1 || (has_carry && T0 <= src1)) env->xcc |= PSR_CARRY; if (((src1 ^ T1 ^ -1) & (src1 ^ T0)) & (1ULL << 63)) env->xcc |= PSR_OVF; @@ -444,7 +444,7 @@ void OPPROTO op_addx_T1_T0_cc(void) env->psr |= PSR_ZERO; if ((int32_t) T0 < 0) env->psr |= PSR_NEG; - if (T0 < src1) + if (T0 < src1 || (has_carry && T0 <= src1)) env->psr |= PSR_CARRY; if (((src1 ^ T1 ^ -1) & (src1 ^ T0)) & (1 << 31)) env->psr |= PSR_OVF; @@ -505,9 +505,9 @@ void OPPROTO op_subx_T1_T0(void) void OPPROTO op_subx_T1_T0_cc(void) { target_ulong src1; - + target_ulong has_carry = FLAG_SET(PSR_CARRY); src1 = T0; - T0 -= T1 + FLAG_SET(PSR_CARRY); + T0 -= T1 + has_carry; env->psr = 0; #ifdef TARGET_SPARC64 if (!(T0 & 0xffffffff)) @@ -525,7 +525,7 @@ void OPPROTO op_subx_T1_T0_cc(void) env->xcc |= PSR_ZERO; if ((int64_t) T0 < 0) env->xcc |= PSR_NEG; - if (src1 < T1) + if (src1 < T1 || (has_carry && src1 <= T1)) env->xcc |= PSR_CARRY; if (((src1 ^ T1) & (src1 ^ T0)) & (1ULL << 63)) env->xcc |= PSR_OVF; @@ -534,7 +534,7 @@ void OPPROTO op_subx_T1_T0_cc(void) env->psr |= PSR_ZERO; if ((int32_t) T0 < 0) env->psr |= PSR_NEG; - if (src1 < T1) + if (src1 < T1 || (has_carry && src1 <= T1)) env->psr |= PSR_CARRY; if (((src1 ^ T1) & (src1 ^ T0)) & (1 << 31)) env->psr |= PSR_OVF; ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [Qemu-devel] [PATCH] SPARC target : Fix carry flag update in addxcc and subxcc ops 2006-04-08 13:46 [Qemu-devel] [PATCH] SPARC target : Fix carry flag update in addxcc and subxcc ops Even Rouault @ 2006-04-09 20:38 ` Paul Brook 2006-04-10 18:04 ` [Qemu-devel] [PATCH] SPARC target : Fix carry flag update inaddxcc and subxc Blue Swirl 2006-04-10 17:57 ` [Qemu-devel] [PATCH] SPARC target : Fix carry flag update in addxccand subxc Blue Swirl 1 sibling, 1 reply; 7+ messages in thread From: Paul Brook @ 2006-04-09 20:38 UTC (permalink / raw) To: qemu-devel On Saturday 08 April 2006 14:46, Even Rouault wrote: > I send a patch that should fix a bug in the update of carry flag for addxcc > and subxcc instructions when the carry flag is set before the evaluation of > the instruction. > (the fix is identical to what is done in the similar instruction > op_adcl_T0_T1_cc for arm target) if ((T0 & 0xffffffff) < (src1 & 0xffffffff)) env->psr |= PSR_CARRY; Doesn't this condition in addx and the corresponding line in subx need similar treatment? Paul ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [Qemu-devel] [PATCH] SPARC target : Fix carry flag update inaddxcc and subxc 2006-04-09 20:38 ` Paul Brook @ 2006-04-10 18:04 ` Blue Swirl 2006-04-10 18:13 ` Paul Brook 2006-04-10 18:46 ` Laurent Desnogues 0 siblings, 2 replies; 7+ messages in thread From: Blue Swirl @ 2006-04-10 18:04 UTC (permalink / raw) To: qemu-devel, paul >Doesn't this condition in addx and the corresponding line in subx need >similar >treatment? They don't change the flags. _________________________________________________________________ FREE pop-up blocking with the new MSN Toolbar - get it now! http://toolbar.msn.click-url.com/go/onm00200415ave/direct/01/ ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [Qemu-devel] [PATCH] SPARC target : Fix carry flag update inaddxcc and subxc 2006-04-10 18:04 ` [Qemu-devel] [PATCH] SPARC target : Fix carry flag update inaddxcc and subxc Blue Swirl @ 2006-04-10 18:13 ` Paul Brook 2006-04-10 18:46 ` Laurent Desnogues 1 sibling, 0 replies; 7+ messages in thread From: Paul Brook @ 2006-04-10 18:13 UTC (permalink / raw) To: qemu-devel On Monday 10 April 2006 19:04, Blue Swirl wrote: > >Doesn't this condition in addx and the corresponding line in subx need > >similar > >treatment? > > They don't change the flags. It certainly look like they do. In particular if TARGET_SPARC64 we have if ((T0 & 0xffffffff) < (src1 & 0xffffffff)) env->psr |= PSR_CARRY; But if !TARGET_SPARC64 we have - if (T0 < src1) + if (T0 < src1 || (has_carry && T0 <= src1)) env->psr |= PSR_CARRY; I'd expect these two to be the same (modulo the explicit truncation in the first case). Paul ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [Qemu-devel] [PATCH] SPARC target : Fix carry flag update inaddxcc and subxc 2006-04-10 18:04 ` [Qemu-devel] [PATCH] SPARC target : Fix carry flag update inaddxcc and subxc Blue Swirl 2006-04-10 18:13 ` Paul Brook @ 2006-04-10 18:46 ` Laurent Desnogues 2006-04-10 20:18 ` Even Rouault 1 sibling, 1 reply; 7+ messages in thread From: Laurent Desnogues @ 2006-04-10 18:46 UTC (permalink / raw) To: qemu-devel Blue Swirl a écrit : >> Doesn't this condition in addx and the corresponding line in subx need >> similar >> treatment? > > They don't change the flags. ADDX (now named ADDC in v9) doesn't change the flags, while ADDXcc (ADDCcc) does. The cc versions also compute overflow. cf. SPARC v9 on www.sparg.org Laurent ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [Qemu-devel] [PATCH] SPARC target : Fix carry flag update inaddxcc and subxc 2006-04-10 18:46 ` Laurent Desnogues @ 2006-04-10 20:18 ` Even Rouault 0 siblings, 0 replies; 7+ messages in thread From: Even Rouault @ 2006-04-10 20:18 UTC (permalink / raw) To: qemu-devel [-- Attachment #1: Type: text/plain, Size: 1770 bytes --] To be clear, I just ran into the problem of the update of the carry flag but I'm not at all a specialist of SPARC assembly. From what I've understood, Paul is certainly right when suggesting to add a fix for the SPARC64 case (for the addxcc and subxcc, not addx and subx) and I send a new version of the patch (qemu-sparc-carry-xcc-2.patch) I've also tried to take into account Blue Swirl's suggestion of storing the intermediate results of the addition T0 + FLAG_SET(PSR_CARRY), but the result wasn't correct in all cases (specifically if T0=0xFFFFFFFF). I think we really need a '<' and '<=' comparison. However, I've tried to refactor a bit the code to save some comparisons in another version of the patch (qemu-sparc-carry-xcc-3.patch), really close to the arm code, and hopefully equivalent to qemu-sparc-carry-xcc-2.patch (but less sexy). As far as the V flag is concerned, mmm, I'm not really sure whether we should change something in the sparc code. If we compare to the arm code, we don't take into account the fact that the carry flag is set before. We'd probably need some extensive tests and their associated expected results. Even Le Lundi 10 Avril 2006 20:46, Laurent Desnogues a écrit : > Blue Swirl a écrit : > >> Doesn't this condition in addx and the corresponding line in subx need > >> similar > >> treatment? > > > > They don't change the flags. > > ADDX (now named ADDC in v9) doesn't change the flags, while ADDXcc > (ADDCcc) does. The cc versions also compute overflow. > > cf. SPARC v9 on www.sparg.org > > > Laurent > > > > _______________________________________________ > Qemu-devel mailing list > Qemu-devel@nongnu.org > http://lists.nongnu.org/mailman/listinfo/qemu-devel [-- Attachment #2: qemu-sparc-carry-xcc-ops-3.patch --] [-- Type: text/x-diff, Size: 3724 bytes --] ? qemu-sparc-carry-xcc-ops-2.patch ? qemu-sparc-carry-xcc-ops-3.patch ? qemu-sparc-carry-xcc-ops.patch Index: op.c =================================================================== RCS file: /sources/qemu/qemu/target-sparc/op.c,v retrieving revision 1.18 diff -u -p -r1.18 op.c --- op.c 30 Oct 2005 17:28:50 -0000 1.18 +++ op.c 10 Apr 2006 20:03:37 -0000 @@ -415,28 +415,50 @@ void OPPROTO op_addx_T1_T0(void) void OPPROTO op_addx_T1_T0_cc(void) { target_ulong src1; - src1 = T0; - T0 += T1 + FLAG_SET(PSR_CARRY); - env->psr = 0; + if (FLAG_SET(PSR_CARRY)) + { + T0 += T1 + 1; + env->psr = 0; +#ifdef TARGET_SPARC64 + if ((T0 & 0xffffffff) <= (src1 & 0xffffffff)) + env->psr |= PSR_CARRY; + env->xcc = 0; + if (T0 <= src1) + env->xcc |= PSR_CARRY; +#else + if (T0 <= src1) + env->psr |= PSR_CARRY; +#endif + } + else + { + T0 += T1; + env->psr = 0; +#ifdef TARGET_SPARC64 + if ((T0 & 0xffffffff) < (src1 & 0xffffffff)) + env->psr |= PSR_CARRY; + env->xcc = 0; + if (T0 < src1) + env->xcc |= PSR_CARRY; +#else + if (T0 < src1) + env->psr |= PSR_CARRY; +#endif + } #ifdef TARGET_SPARC64 if (!(T0 & 0xffffffff)) env->psr |= PSR_ZERO; if ((int32_t) T0 < 0) env->psr |= PSR_NEG; - if ((T0 & 0xffffffff) < (src1 & 0xffffffff)) - env->psr |= PSR_CARRY; if ((((src1 & 0xffffffff) ^ (T1 & 0xffffffff) ^ -1) & ((src1 & 0xffffffff) ^ (T0 & 0xffffffff))) & (1 << 31)) env->psr |= PSR_OVF; - env->xcc = 0; if (!T0) env->xcc |= PSR_ZERO; if ((int64_t) T0 < 0) env->xcc |= PSR_NEG; - if (T0 < src1) - env->xcc |= PSR_CARRY; if (((src1 ^ T1 ^ -1) & (src1 ^ T0)) & (1ULL << 63)) env->xcc |= PSR_OVF; #else @@ -444,8 +466,6 @@ void OPPROTO op_addx_T1_T0_cc(void) env->psr |= PSR_ZERO; if ((int32_t) T0 < 0) env->psr |= PSR_NEG; - if (T0 < src1) - env->psr |= PSR_CARRY; if (((src1 ^ T1 ^ -1) & (src1 ^ T0)) & (1 << 31)) env->psr |= PSR_OVF; #endif @@ -505,28 +525,50 @@ void OPPROTO op_subx_T1_T0(void) void OPPROTO op_subx_T1_T0_cc(void) { target_ulong src1; - src1 = T0; - T0 -= T1 + FLAG_SET(PSR_CARRY); - env->psr = 0; + if (FLAG_SET(PSR_CARRY)) + { + T0 -= T1 + 1; + env->psr = 0; +#ifdef TARGET_SPARC64 + if ((src1 & 0xffffffff) <= (T1 & 0xffffffff)) + env->psr |= PSR_CARRY; + env->xcc = 0; + if (src1 <= T1) + env->xcc |= PSR_CARRY; +#else + if (src1 <= T1) + env->psr |= PSR_CARRY; +#endif + } + else + { + T0 -= T1; + env->psr = 0; +#ifdef TARGET_SPARC64 + if ((src1 & 0xffffffff) < (T1 & 0xffffffff)) + env->psr |= PSR_CARRY; + env->xcc = 0; + if (src1 < T1) + env->xcc |= PSR_CARRY; +#else + if (src1 < T1) + env->psr |= PSR_CARRY; +#endif + } #ifdef TARGET_SPARC64 if (!(T0 & 0xffffffff)) env->psr |= PSR_ZERO; if ((int32_t) T0 < 0) env->psr |= PSR_NEG; - if ((src1 & 0xffffffff) < (T1 & 0xffffffff)) - env->psr |= PSR_CARRY; if ((((src1 & 0xffffffff) ^ (T1 & 0xffffffff)) & ((src1 & 0xffffffff) ^ (T0 & 0xffffffff))) & (1 << 31)) env->psr |= PSR_OVF; - env->xcc = 0; if (!T0) env->xcc |= PSR_ZERO; if ((int64_t) T0 < 0) env->xcc |= PSR_NEG; - if (src1 < T1) - env->xcc |= PSR_CARRY; if (((src1 ^ T1) & (src1 ^ T0)) & (1ULL << 63)) env->xcc |= PSR_OVF; #else @@ -534,8 +576,6 @@ void OPPROTO op_subx_T1_T0_cc(void) env->psr |= PSR_ZERO; if ((int32_t) T0 < 0) env->psr |= PSR_NEG; - if (src1 < T1) - env->psr |= PSR_CARRY; if (((src1 ^ T1) & (src1 ^ T0)) & (1 << 31)) env->psr |= PSR_OVF; #endif [-- Attachment #3: qemu-sparc-carry-xcc-ops-2.patch --] [-- Type: text/x-diff, Size: 2945 bytes --] ? qemu-sparc-carry-xcc-ops-2.patch ? qemu-sparc-carry-xcc-ops.patch Index: op.c =================================================================== RCS file: /sources/qemu/qemu/target-sparc/op.c,v retrieving revision 1.18 diff -u -p -r1.18 op.c --- op.c 30 Oct 2005 17:28:50 -0000 1.18 +++ op.c 10 Apr 2006 18:57:46 -0000 @@ -415,16 +415,17 @@ void OPPROTO op_addx_T1_T0(void) void OPPROTO op_addx_T1_T0_cc(void) { target_ulong src1; - + target_ulong has_carry = FLAG_SET(PSR_CARRY); src1 = T0; - T0 += T1 + FLAG_SET(PSR_CARRY); + T0 += T1 + has_carry; env->psr = 0; #ifdef TARGET_SPARC64 if (!(T0 & 0xffffffff)) env->psr |= PSR_ZERO; if ((int32_t) T0 < 0) env->psr |= PSR_NEG; - if ((T0 & 0xffffffff) < (src1 & 0xffffffff)) + if (((T0 & 0xffffffff) < (src1 & 0xffffffff)) || + (has_carry && ((T0 & 0xffffffff) <= (src1 & 0xffffffff)))) env->psr |= PSR_CARRY; if ((((src1 & 0xffffffff) ^ (T1 & 0xffffffff) ^ -1) & ((src1 & 0xffffffff) ^ (T0 & 0xffffffff))) & (1 << 31)) @@ -435,7 +436,7 @@ void OPPROTO op_addx_T1_T0_cc(void) env->xcc |= PSR_ZERO; if ((int64_t) T0 < 0) env->xcc |= PSR_NEG; - if (T0 < src1) + if (T0 < src1 || (has_carry && T0 <= src1)) env->xcc |= PSR_CARRY; if (((src1 ^ T1 ^ -1) & (src1 ^ T0)) & (1ULL << 63)) env->xcc |= PSR_OVF; @@ -444,7 +445,7 @@ void OPPROTO op_addx_T1_T0_cc(void) env->psr |= PSR_ZERO; if ((int32_t) T0 < 0) env->psr |= PSR_NEG; - if (T0 < src1) + if (T0 < src1 || (has_carry && T0 <= src1)) env->psr |= PSR_CARRY; if (((src1 ^ T1 ^ -1) & (src1 ^ T0)) & (1 << 31)) env->psr |= PSR_OVF; @@ -505,16 +506,17 @@ void OPPROTO op_subx_T1_T0(void) void OPPROTO op_subx_T1_T0_cc(void) { target_ulong src1; - + target_ulong has_carry = FLAG_SET(PSR_CARRY); src1 = T0; - T0 -= T1 + FLAG_SET(PSR_CARRY); + T0 -= T1 + has_carry; env->psr = 0; #ifdef TARGET_SPARC64 if (!(T0 & 0xffffffff)) env->psr |= PSR_ZERO; if ((int32_t) T0 < 0) env->psr |= PSR_NEG; - if ((src1 & 0xffffffff) < (T1 & 0xffffffff)) + if (((src1 & 0xffffffff) < (T1 & 0xffffffff)) || + (has_carry && ((src1 & 0xffffffff) <= (T1 & 0xffffffff)))) env->psr |= PSR_CARRY; if ((((src1 & 0xffffffff) ^ (T1 & 0xffffffff)) & ((src1 & 0xffffffff) ^ (T0 & 0xffffffff))) & (1 << 31)) @@ -525,7 +527,7 @@ void OPPROTO op_subx_T1_T0_cc(void) env->xcc |= PSR_ZERO; if ((int64_t) T0 < 0) env->xcc |= PSR_NEG; - if (src1 < T1) + if (src1 < T1 || (has_carry && src1 <= T1)) env->xcc |= PSR_CARRY; if (((src1 ^ T1) & (src1 ^ T0)) & (1ULL << 63)) env->xcc |= PSR_OVF; @@ -534,7 +536,7 @@ void OPPROTO op_subx_T1_T0_cc(void) env->psr |= PSR_ZERO; if ((int32_t) T0 < 0) env->psr |= PSR_NEG; - if (src1 < T1) + if (src1 < T1 || (has_carry && src1 <= T1)) env->psr |= PSR_CARRY; if (((src1 ^ T1) & (src1 ^ T0)) & (1 << 31)) env->psr |= PSR_OVF; ^ permalink raw reply [flat|nested] 7+ messages in thread
* RE: [Qemu-devel] [PATCH] SPARC target : Fix carry flag update in addxccand subxc 2006-04-08 13:46 [Qemu-devel] [PATCH] SPARC target : Fix carry flag update in addxcc and subxcc ops Even Rouault 2006-04-09 20:38 ` Paul Brook @ 2006-04-10 17:57 ` Blue Swirl 1 sibling, 0 replies; 7+ messages in thread From: Blue Swirl @ 2006-04-10 17:57 UTC (permalink / raw) To: qemu-devel, even.rouault >I send a patch that should fix a bug in the update of carry flag for addxcc >and subxcc instructions when the carry flag is set before the evaluation of >the instruction. >(the fix is identical to what is done in the similar instruction >op_adcl_T0_T1_cc for arm target) Looks good, but what about V flag? Instead of adding a new condition, perhaps you could store the intermediate results of addition, like T0 + FLAG_SET(PSR_CARRY) and use that later in the comparison? BTW: ARM env->NZF idea could be used to Sparc as well. _________________________________________________________________ FREE pop-up blocking with the new MSN Toolbar - get it now! http://toolbar.msn.click-url.com/go/onm00200415ave/direct/01/ ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2006-04-10 20:19 UTC | newest] Thread overview: 7+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2006-04-08 13:46 [Qemu-devel] [PATCH] SPARC target : Fix carry flag update in addxcc and subxcc ops Even Rouault 2006-04-09 20:38 ` Paul Brook 2006-04-10 18:04 ` [Qemu-devel] [PATCH] SPARC target : Fix carry flag update inaddxcc and subxc Blue Swirl 2006-04-10 18:13 ` Paul Brook 2006-04-10 18:46 ` Laurent Desnogues 2006-04-10 20:18 ` Even Rouault 2006-04-10 17:57 ` [Qemu-devel] [PATCH] SPARC target : Fix carry flag update in addxccand subxc Blue Swirl
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