From e62bb22a4b6fa21c1138ab1d3e999d84b27b5e2b Mon Sep 17 00:00:00 2001 From: Mike Frysinger Date: Mon, 19 Mar 2012 05:06:23 +0000 Subject: [PATCH] sim: bfin: fix corner case Logical shift issues From: Robin Getz Overflow with shift operations happens independently of saturation, but we have the logic merged. Extend the lshift function so that callers can tell it when to handle each independently, and then do so when it's needed. Signed-off-by: Robin Getz Signed-off-by: Mike Frysinger --- sim/bfin/ChangeLog | 11 +++++ sim/bfin/bfin-sim.c | 98 ++++++++++++++++++++++++--------------------- 2 files changed, 64 insertions(+), 45 deletions(-) diff --git a/sim/bfin/ChangeLog b/sim/bfin/ChangeLog index bac48f38192..35863c933d2 100644 --- a/sim/bfin/ChangeLog +++ b/sim/bfin/ChangeLog @@ -1,3 +1,14 @@ +2012-03-19 Robin Getz + Mike Frysinger + + * bfin-sim.c (lshift): Add an overflow flag. Delete now unused + i, j, and tmp vars. Add a new v_i var. Split the overflow logic + out from the saturate logic. Do not set V ASTAT bits when working + with accumulators. + (decode_ALU2op_0): Add new argument to lshift call. + (decode_LOGI2op_0, decode_dsp32shift_0, decode_dsp32shiftimm_0): + Likewise. + 2012-03-18 Mike Frysinger * dv-bfin_ebiu_amc.c (struct bfin_ebiu_amc): Add bank_base. diff --git a/sim/bfin/bfin-sim.c b/sim/bfin/bfin-sim.c index ef7362bc936..2c93e04a185 100644 --- a/sim/bfin/bfin-sim.c +++ b/sim/bfin/bfin-sim.c @@ -748,12 +748,12 @@ lshiftrt (SIM_CPU *cpu, bu64 val, int cnt, int size) } static bu64 -lshift (SIM_CPU *cpu, bu64 val, int cnt, int size, bool saturate) +lshift (SIM_CPU *cpu, bu64 val, int cnt, int size, bool saturate, bool overflow) { - int i, j, real_cnt = cnt > size ? size : cnt; + int v_i, real_cnt = cnt > size ? size : cnt; bu64 sgn = ~((val >> (size - 1)) - 1); int mask_cnt = size - 1; - bu64 masked, new_val = val, tmp; + bu64 masked, new_val = val; bu64 mask = ~0; mask <<= mask_cnt; @@ -777,31 +777,35 @@ lshift (SIM_CPU *cpu, bu64 val, int cnt, int size, bool saturate) However, it's a little more complex than looking at sign bits, we need to see if we are shifting the sign information away... */ - tmp = val & ((~mask << 1) | 1); - - j = 0; - for (i = 1; i <= real_cnt && saturate; i++) - { - if ((tmp & ((bu64)1 << (size - 1))) != - (((val >> mask_cnt) & 0x1) << mask_cnt)) - j++; - tmp <<= 1; - } - saturate &= (!sgn && (new_val & (1 << mask_cnt))) - || (sgn && !(new_val & (1 << mask_cnt))); + if (((val << cnt) >> size) == 0 + || (((val << cnt) >> size) == ~(~0 << cnt) + && ((new_val >> (size - 1)) & 0x1))) + v_i = 0; + else + v_i = 1; switch (size) { case 16: - if (j || (saturate && (new_val & mask))) - new_val = sgn == 0 ? 0x7fff : 0x8000, saturate = 1; new_val &= 0xFFFF; + if (saturate && (v_i || ((val >> (size - 1)) != (new_val >> (size - 1))))) + { + new_val = (val >> (size - 1)) == 0 ? 0x7fff : 0x8000; + v_i = 1; + } break; case 32: new_val &= 0xFFFFFFFF; masked &= 0xFFFFFFFF; - if (j || (saturate && ((sgn != masked) || (!sgn && new_val == 0)))) - new_val = sgn == 0 ? 0x7fffffff : 0x80000000, saturate = 1; + sgn &= 0xFFFFFFFF; + if (saturate + && (v_i + || (sgn != masked) + || (!sgn && new_val == 0 && val != 0))) + { + new_val = sgn == 0 ? 0x7fffffff : 0x80000000; + v_i = 1; + } break; case 40: new_val &= 0xFFFFFFFFFFull; @@ -814,9 +818,13 @@ lshift (SIM_CPU *cpu, bu64 val, int cnt, int size, bool saturate) SET_ASTATREG (an, new_val >> (size - 1)); SET_ASTATREG (az, new_val == 0); - SET_ASTATREG (v, !!(saturate || j)); - if (saturate || j) - SET_ASTATREG (vs, 1); + if (size != 40) + { + SET_ASTATREG (v, overflow && v_i); + if (overflow && v_i) + SET_ASTATREG (vs, 1); + } + return new_val; } @@ -2557,7 +2565,7 @@ decode_ALU2op_0 (SIM_CPU *cpu, bu16 iw0) else if (opc == 2) { TRACE_INSN (cpu, "R%i <<= R%i;", dst, src); - SET_DREG (dst, lshift (cpu, DREG (dst), DREG (src), 32, 0)); + SET_DREG (dst, lshift (cpu, DREG (dst), DREG (src), 32, 0, 0)); } else if (opc == 3) { @@ -2760,7 +2768,7 @@ decode_LOGI2op_0 (SIM_CPU *cpu, bu16 iw0) TRACE_INSN (cpu, "R%i <<= %s;", dst, uimm_str); if (INSN_LEN == 8) illegal_instruction_combination (cpu); - SET_DREG (dst, lshift (cpu, DREG (dst), uimm, 32, 0)); + SET_DREG (dst, lshift (cpu, DREG (dst), uimm, 32, 0, 0)); } } @@ -5158,7 +5166,7 @@ decode_dsp32shift_0 (SIM_CPU *cpu, bu16 iw0, bu16 iw1) if (shft <= 0) val = ashiftrt (cpu, val, -shft, 16); else - val = lshift (cpu, val, shft, 16, sop == 1); + val = lshift (cpu, val, shft, 16, sop == 1, 1); if ((HLs & 2) == 0) STORE (DREG (dst0), REG_H_L (DREG (dst0), val)); @@ -5219,7 +5227,7 @@ decode_dsp32shift_0 (SIM_CPU *cpu, bu16 iw0, bu16 iw1) if (shft <= 0) val = ashiftrt (cpu, val, -shft, 40); else - val = lshift (cpu, val, shft, 40, 0); + val = lshift (cpu, val, shft, 40, 0, 0); STORE (AXREG (HLs), (val >> 32) & 0xff); STORE (AWREG (HLs), (val & 0xffffffff)); @@ -5239,7 +5247,7 @@ decode_dsp32shift_0 (SIM_CPU *cpu, bu16 iw0, bu16 iw1) if (shft <= 0) val = lshiftrt (cpu, val, -shft, 40); else - val = lshift (cpu, val, shft, 40, 0); + val = lshift (cpu, val, shft, 40, 0, 0); STORE (AXREG (HLs), (val >> 32) & 0xff); STORE (AWREG (HLs), (val & 0xffffffff)); @@ -5267,9 +5275,9 @@ decode_dsp32shift_0 (SIM_CPU *cpu, bu16 iw0, bu16 iw1) } else { - val0 = lshift (cpu, val0, shft, 16, sop == 1); + val0 = lshift (cpu, val0, shft, 16, sop == 1, 1); astat = ASTAT; - val1 = lshift (cpu, val1, shft, 16, sop == 1); + val1 = lshift (cpu, val1, shft, 16, sop == 1, 1); } SET_ASTAT (ASTAT | astat); STORE (DREG (dst0), (val1 << 16) | val0); @@ -5294,7 +5302,7 @@ decode_dsp32shift_0 (SIM_CPU *cpu, bu16 iw0, bu16 iw1) STORE (DREG (dst0), ashiftrt (cpu, v, -shft, 32)); } else - STORE (DREG (dst0), lshift (cpu, v, shft, 32, sop == 1)); + STORE (DREG (dst0), lshift (cpu, v, shft, 32, sop == 1, 1)); } else if (sop == 3 && sopcde == 2) { @@ -5330,9 +5338,9 @@ decode_dsp32shift_0 (SIM_CPU *cpu, bu16 iw0, bu16 iw1) } else { - val0 = lshift (cpu, val0, shft, 16, 0); + val0 = lshift (cpu, val0, shft, 16, 0, 0); astat = ASTAT; - val1 = lshift (cpu, val1, shft, 16, 0); + val1 = lshift (cpu, val1, shft, 16, 0, 0); } SET_ASTAT (ASTAT | astat); STORE (DREG (dst0), (val1 << 16) | val0); @@ -5702,7 +5710,7 @@ decode_dsp32shiftimm_0 (SIM_CPU *cpu, bu16 iw0, bu16 iw1) dst0, (HLs & 2) ? 'H' : 'L', src1, (HLs & 1) ? 'H' : 'L', newimmag); if (newimmag > 16) - result = lshift (cpu, in, 16 - (newimmag & 0xF), 16, 0); + result = lshift (cpu, in, 16 - (newimmag & 0xF), 16, 0, 1); else result = ashiftrt (cpu, in, newimmag, 16); } @@ -5711,14 +5719,14 @@ decode_dsp32shiftimm_0 (SIM_CPU *cpu, bu16 iw0, bu16 iw1) TRACE_INSN (cpu, "R%i.%c = R%i.%c << %i (S);", dst0, (HLs & 2) ? 'H' : 'L', src1, (HLs & 1) ? 'H' : 'L', immag); - result = lshift (cpu, in, immag, 16, 1); + result = lshift (cpu, in, immag, 16, 1, 1); } else if (sop == 1 && bit8) { TRACE_INSN (cpu, "R%i.%c = R%i.%c >>> %i (S);", dst0, (HLs & 2) ? 'H' : 'L', src1, (HLs & 1) ? 'H' : 'L', immag); - result = lshift (cpu, in, immag, 16, 1); + result = lshift (cpu, in, immag, 16, 1, 1); } else if (sop == 2 && bit8) { @@ -5732,7 +5740,7 @@ decode_dsp32shiftimm_0 (SIM_CPU *cpu, bu16 iw0, bu16 iw1) TRACE_INSN (cpu, "R%i.%c = R%i.%c << %i;", dst0, (HLs & 2) ? 'H' : 'L', src1, (HLs & 1) ? 'H' : 'L', immag); - result = lshift (cpu, in, immag, 16, 0); + result = lshift (cpu, in, immag, 16, 0, 1); } else illegal_instruction (cpu); @@ -5820,9 +5828,9 @@ decode_dsp32shiftimm_0 (SIM_CPU *cpu, bu16 iw0, bu16 iw1) TRACE_INSN (cpu, "R%i = R%i << %i (V,S);", dst0, src1, count); if (count >= 0) { - val0 = lshift (cpu, val0, count, 16, 1); + val0 = lshift (cpu, val0, count, 16, 1, 1); astat = ASTAT; - val1 = lshift (cpu, val1, count, 16, 1); + val1 = lshift (cpu, val1, count, 16, 1, 1); } else { @@ -5857,9 +5865,9 @@ decode_dsp32shiftimm_0 (SIM_CPU *cpu, bu16 iw0, bu16 iw1) bu32 astat; TRACE_INSN (cpu, "R%i = R%i << %i (V);", dst0, src1, count); - val0 = lshift (cpu, val0, count, 16, 0); + val0 = lshift (cpu, val0, count, 16, 0, 1); astat = ASTAT; - val1 = lshift (cpu, val1, count, 16, 0); + val1 = lshift (cpu, val1, count, 16, 0, 1); SET_ASTAT (ASTAT | astat); STORE (DREG (dst0), val0 | (val1 << 16)); @@ -5876,9 +5884,9 @@ decode_dsp32shiftimm_0 (SIM_CPU *cpu, bu16 iw0, bu16 iw1) if (count & 0x10) { - val0 = lshift (cpu, val0, 16 - (count & 0xF), 16, 0); + val0 = lshift (cpu, val0, 16 - (count & 0xF), 16, 0, 1); astat = ASTAT; - val1 = lshift (cpu, val1, 16 - (count & 0xF), 16, 0); + val1 = lshift (cpu, val1, 16 - (count & 0xF), 16, 0, 1); } else { @@ -5896,7 +5904,7 @@ decode_dsp32shiftimm_0 (SIM_CPU *cpu, bu16 iw0, bu16 iw1) int count = imm6 (immag); TRACE_INSN (cpu, "R%i = R%i << %i (S);", dst0, src1, count); - STORE (DREG (dst0), lshift (cpu, DREG (src1), count, 32, 1)); + STORE (DREG (dst0), lshift (cpu, DREG (src1), count, 32, 1, 1)); } else if (sop == 2 && sopcde == 2) { @@ -5905,7 +5913,7 @@ decode_dsp32shiftimm_0 (SIM_CPU *cpu, bu16 iw0, bu16 iw1) TRACE_INSN (cpu, "R%i = R%i >> %i;", dst0, src1, count); if (count < 0) - STORE (DREG (dst0), lshift (cpu, DREG (src1), -count, 32, 0)); + STORE (DREG (dst0), lshift (cpu, DREG (src1), -count, 32, 0, 1)); else STORE (DREG (dst0), lshiftrt (cpu, DREG (src1), count, 32)); } @@ -5931,7 +5939,7 @@ decode_dsp32shiftimm_0 (SIM_CPU *cpu, bu16 iw0, bu16 iw1) TRACE_INSN (cpu, "R%i = R%i >>> %i;", dst0, src1, count); if (count < 0) - STORE (DREG (dst0), lshift (cpu, DREG (src1), -count, 32, 0)); + STORE (DREG (dst0), lshift (cpu, DREG (src1), -count, 32, 0, 1)); else STORE (DREG (dst0), ashiftrt (cpu, DREG (src1), count, 32)); } -- 2.30.2