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BISB/BICB: keep MSB for register operations

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folkert van heusden 2024-05-02 01:32:21 +02:00
parent 6974234d5e
commit 0a0807e1ad
Signed by untrusted user who does not match committer: folkert
GPG key ID: 6B6455EDFEED3BD1
1 changed files with 45 additions and 20 deletions
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27
cpu.cpp
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@ -643,6 +643,17 @@ bool cpu::double_operand_instructions(const uint16_t instr)
case 0b100: { // BIC/BICB Bit Clear Word/Byte case 0b100: { // BIC/BICB Bit Clear Word/Byte
gam_rc_t g_src = getGAM(src_mode, src_reg, word_mode, rm_cur); gam_rc_t g_src = getGAM(src_mode, src_reg, word_mode, rm_cur);
if (dst_mode == 0) {
addToMMR1(g_src); // keep here because of order of updates
uint16_t v = getRegister(dst_reg); // need the full word
uint16_t result = v & ~g_src.value.value();
setRegister(dst_reg, result);
setPSW_flags_nzv(result, word_mode);
}
else {
auto g_dst = getGAM(dst_mode, dst_reg, word_mode, rm_cur); auto g_dst = getGAM(dst_mode, dst_reg, word_mode, rm_cur);
addToMMR1(g_dst); addToMMR1(g_dst);
@ -652,14 +663,27 @@ bool cpu::double_operand_instructions(const uint16_t instr)
if (put_result(g_dst, result)) if (put_result(g_dst, result))
setPSW_flags_nzv(result, word_mode); setPSW_flags_nzv(result, word_mode);
}
return true; return true;
} }
case 0b101: { // BIS/BISB Bit Set Word/Byte case 0b101: { // BIS/BISB Bit Set Word/Byte
// TODO: retain MSB for register operations?
gam_rc_t g_src = getGAM(src_mode, src_reg, word_mode, rm_cur); gam_rc_t g_src = getGAM(src_mode, src_reg, word_mode, rm_cur);
if (dst_mode == 0) {
addToMMR1(g_src); // keep here because of order of updates
uint16_t v = getRegister(dst_reg); // need the full word
uint16_t result = v | g_src.value.value();
setRegister(dst_reg, result);
setPSW_n(SIGN(result, word_mode));
setPSW_z(IS_0(result, word_mode));
setPSW_v(false);
}
else {
auto g_dst = getGAM(dst_mode, dst_reg, word_mode, rm_cur); auto g_dst = getGAM(dst_mode, dst_reg, word_mode, rm_cur);
addToMMR1(g_dst); addToMMR1(g_dst);
@ -672,6 +696,7 @@ bool cpu::double_operand_instructions(const uint16_t instr)
setPSW_z(IS_0(result, word_mode)); setPSW_z(IS_0(result, word_mode));
setPSW_v(false); setPSW_v(false);
} }
}
return true; return true;
} }