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double trap could push invalid data into MMR1

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folkert van heusden 2023-03-26 11:59:00 +02:00
parent 3acf43acf7
commit e1aed28f46
Signed by untrusted user who does not match committer: folkert
GPG key ID: 6B6455EDFEED3BD1
1 changed files with 7 additions and 4 deletions
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11
cpu.cpp
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@ -336,6 +336,7 @@ gam_rc_t cpu::getGAM(const uint8_t mode, const uint8_t reg, const word_mode_t wo
break; break;
case 3: // @(Rn)+ / @#a case 3: // @(Rn)+ / @#a
g.addr = b->read(getRegister(reg, mode_selection), wm_word, mode_selection, false, isR7_space); g.addr = b->read(getRegister(reg, mode_selection), wm_word, mode_selection, false, isR7_space);
// might be wrong: the adds should happen when the read is really performed, because of traps
addRegister(reg, mode_selection, 2); addRegister(reg, mode_selection, 2);
addToMMR1(mode, reg, word_mode); addToMMR1(mode, reg, word_mode);
g.space = d_space; g.space = d_space;
@ -1609,14 +1610,16 @@ void cpu::trap(uint16_t vector, const int new_ipl, const bool is_interrupt)
} }
} }
else { else {
before_psw = getPSW(); bool mmr1_locked = b->getMMR0() & 0160000;
before_pc = getPC();
if ((b->getMMR0() & 0160000) == 0) { before_psw = getPSW();
if (!mmr1_locked)
b->addToMMR1(-2, 6); b->addToMMR1(-2, 6);
before_pc = getPC();
if (!mmr1_locked)
b->addToMMR1(-2, 6); b->addToMMR1(-2, 6);
} }
}
// make sure the trap vector is retrieved from kernel space // make sure the trap vector is retrieved from kernel space
psw &= 037777; // mask off 14/15 TODO: still required? readWord gets a d_space parameter psw &= 037777; // mask off 14/15 TODO: still required? readWord gets a d_space parameter