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-rw-r--r--src/arch/arm/insts/macromem.cc77
-rw-r--r--src/arch/arm/isa/insts/macromem.isa21
2 files changed, 67 insertions, 31 deletions
diff --git a/src/arch/arm/insts/macromem.cc b/src/arch/arm/insts/macromem.cc
index c03b7ccc1..8a82bd319 100644
--- a/src/arch/arm/insts/macromem.cc
+++ b/src/arch/arm/insts/macromem.cc
@@ -58,8 +58,13 @@ MacroMemOp::MacroMemOp(const char *mnem, ExtMachInst machInst,
{
uint32_t regs = reglist;
uint32_t ones = number_of_ones(reglist);
- // Remember that writeback adds a uop
- numMicroops = ones + (writeback ? 1 : 0) + 1;
+ // Remember that writeback adds a uop or two and the temp register adds one
+ numMicroops = ones + (writeback ? (load ? 2 : 1) : 0) + 1;
+
+ // It's technically legal to do a lot of nothing
+ if (!ones)
+ numMicroops = 1;
+
microOps = new StaticInstPtr[numMicroops];
uint32_t addr = 0;
@@ -70,28 +75,13 @@ MacroMemOp::MacroMemOp(const char *mnem, ExtMachInst machInst,
addr += 4;
StaticInstPtr *uop = microOps;
- StaticInstPtr wbUop;
- if (writeback) {
- if (up) {
- wbUop = new MicroAddiUop(machInst, rn, rn, ones * 4);
- } else {
- wbUop = new MicroSubiUop(machInst, rn, rn, ones * 4);
- }
- }
// Add 0 to Rn and stick it in ureg0.
// This is equivalent to a move.
*uop = new MicroAddiUop(machInst, INTREG_UREG0, rn, 0);
- // Write back at the start for loads. This covers the ldm exception return
- // case where the base needs to be written in the old mode. Stores may need
- // the original value of the base, but they don't change mode and can
- // write back at the end like before.
- if (load && writeback) {
- *++uop = wbUop;
- }
-
unsigned reg = 0;
+ unsigned regIdx = 0;
bool force_user = user & !bits(reglist, 15);
bool exception_ret = user & bits(reglist, 15);
@@ -101,19 +91,28 @@ MacroMemOp::MacroMemOp(const char *mnem, ExtMachInst machInst,
reg++;
replaceBits(regs, reg, 0);
- unsigned regIdx = reg;
+ regIdx = reg;
if (force_user) {
regIdx = intRegInMode(MODE_USER, regIdx);
}
if (load) {
- if (reg == INTREG_PC && exception_ret) {
- // This must be the exception return form of ldm.
- *++uop = new MicroLdrRetUop(machInst, regIdx,
- INTREG_UREG0, up, addr);
+ if (writeback && i == ones - 1) {
+ // If it's a writeback and this is the last register
+ // do the load into a temporary register which we'll move
+ // into the final one later
+ *++uop = new MicroLdrUop(machInst, INTREG_UREG1, INTREG_UREG0,
+ up, addr);
} else {
- *++uop = new MicroLdrUop(machInst, regIdx,
- INTREG_UREG0, up, addr);
+ // Otherwise just do it normally
+ if (reg == INTREG_PC && exception_ret) {
+ // This must be the exception return form of ldm.
+ *++uop = new MicroLdrRetUop(machInst, regIdx,
+ INTREG_UREG0, up, addr);
+ } else {
+ *++uop = new MicroLdrUop(machInst, regIdx,
+ INTREG_UREG0, up, addr);
+ }
}
} else {
*++uop = new MicroStrUop(machInst, regIdx, INTREG_UREG0, up, addr);
@@ -125,8 +124,32 @@ MacroMemOp::MacroMemOp(const char *mnem, ExtMachInst machInst,
addr -= 4;
}
- if (!load && writeback) {
- *++uop = wbUop;
+ if (writeback && ones) {
+ // put the register update after we're done all loading
+ if (up)
+ *++uop = new MicroAddiUop(machInst, rn, rn, ones * 4);
+ else
+ *++uop = new MicroSubiUop(machInst, rn, rn, ones * 4);
+
+ // If this was a load move the last temporary value into place
+ // this way we can't take an exception after we update the base
+ // register.
+ if (load && reg == INTREG_PC && exception_ret) {
+ *++uop = new MicroUopRegMovRet(machInst, 0, INTREG_UREG1);
+ warn("creating instruction with exception return at curTick:%d\n",
+ curTick());
+ } else if (load) {
+ *++uop = new MicroUopRegMov(machInst, regIdx, INTREG_UREG1);
+ if (reg == INTREG_PC) {
+ (*uop)->setFlag(StaticInstBase::IsControl);
+ (*uop)->setFlag(StaticInstBase::IsCondControl);
+ (*uop)->setFlag(StaticInstBase::IsIndirectControl);
+ // This is created as a RAS POP
+ if (rn == INTREG_SP)
+ (*uop)->setFlag(StaticInstBase::IsReturn);
+
+ }
+ }
}
(*uop)->setLastMicroop();
diff --git a/src/arch/arm/isa/insts/macromem.isa b/src/arch/arm/isa/insts/macromem.isa
index d6c929353..15879e0e3 100644
--- a/src/arch/arm/isa/insts/macromem.isa
+++ b/src/arch/arm/isa/insts/macromem.isa
@@ -86,24 +86,27 @@ let {{
'predicate_test': predicateTest},
['IsMicroop'])
- microLdrRetUopCode = '''
+ microRetUopCode = '''
CPSR cpsr = Cpsr;
SCTLR sctlr = Sctlr;
uint32_t newCpsr =
cpsrWriteByInstr(cpsr | CondCodes, Spsr, 0xF, true, sctlr.nmfi);
Cpsr = ~CondCodesMask & newCpsr;
CondCodes = CondCodesMask & newCpsr;
- IWNPC = cSwap(Mem.uw, cpsr.e) | ((Spsr & 0x20) ? 1 : 0);
+ IWNPC = cSwap(%s, cpsr.e) | ((Spsr & 0x20) ? 1 : 0);
ForcedItState = ((((CPSR)Spsr).it2 << 2) & 0xFC)
| (((CPSR)Spsr).it1 & 0x3);
'''
+
microLdrRetUopIop = InstObjParams('ldr_ret_uop', 'MicroLdrRetUop',
'MicroMemOp',
- {'memacc_code': microLdrRetUopCode,
+ {'memacc_code':
+ microRetUopCode % 'Mem.uw',
'ea_code':
'EA = URb + (up ? imm : -imm);',
'predicate_test': condPredicateTest},
- ['IsMicroop','IsNonSpeculative','IsSerializeAfter'])
+ ['IsMicroop','IsNonSpeculative',
+ 'IsSerializeAfter'])
microStrUopCode = "Mem = cSwap(URa.uw, ((CPSR)Cpsr).e);"
microStrUopIop = InstObjParams('str_uop', 'MicroStrUop',
@@ -608,6 +611,13 @@ let {{
'predicate_test': predicateTest},
['IsMicroop'])
+ microUopRegMovRetIop = InstObjParams('movret_uop', 'MicroUopRegMovRet',
+ 'MicroIntMov',
+ {'code': microRetUopCode % 'URb',
+ 'predicate_test': predicateTest},
+ ['IsMicroop', 'IsNonSpeculative',
+ 'IsSerializeAfter'])
+
setPCCPSRDecl = '''
CPSR cpsrOrCondCodes = URc;
SCTLR sctlr = Sctlr;
@@ -634,6 +644,7 @@ let {{
MicroIntRegDeclare.subst(microAddUopIop) + \
MicroIntRegDeclare.subst(microSubUopIop) + \
MicroIntMovDeclare.subst(microUopRegMovIop) + \
+ MicroIntMovDeclare.subst(microUopRegMovRetIop) + \
MicroSetPCCPSRDeclare.subst(microUopSetPCCPSRIop)
decoder_output = MicroIntImmConstructor.subst(microAddiUopIop) + \
@@ -641,6 +652,7 @@ let {{
MicroIntRegConstructor.subst(microAddUopIop) + \
MicroIntRegConstructor.subst(microSubUopIop) + \
MicroIntMovConstructor.subst(microUopRegMovIop) + \
+ MicroIntMovConstructor.subst(microUopRegMovRetIop) + \
MicroSetPCCPSRConstructor.subst(microUopSetPCCPSRIop)
exec_output = PredOpExecute.subst(microAddiUopIop) + \
@@ -648,6 +660,7 @@ let {{
PredOpExecute.subst(microAddUopIop) + \
PredOpExecute.subst(microSubUopIop) + \
PredOpExecute.subst(microUopRegMovIop) + \
+ PredOpExecute.subst(microUopRegMovRetIop) + \
PredOpExecute.subst(microUopSetPCCPSRIop)
}};
generated by cgit v1.2.3 (git 2.25.1) at 2024-10-30 16:00:24 +0000