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lua-6502
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bugfixes for extended/illegal opcodes

This commit is contained in:
Jorj Bauer 2018-06-05 08:46:08 -04:00
parent f24e38c982
commit 515f4c7a98
1 changed files with 6 additions and 5 deletions
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11
6502.lua
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@ -402,7 +402,7 @@ _M.opcodes = {
[0xC0] = { _M.optype.CPY , _M.addrmode.IMM , 2 },
[0xC1] = { _M.optype.CMP , _M.addrmode.INX , 6 }, -- [2]
[0xC2] = { _M.optype.ILLEGAL, _M.addrmode.ILLEGAL, 2 },
[0xC3] = { _M.optype.DCP, _M.addrmode.INX, 2 }, -- fixme -- cycle count of this illegal instruction?
[0xC3] = { _M.optype.ILLEGAL, _M.addrmode.ILLEGAL, 2 }, -- fixme -- cycle count of this illegal instruction?
[0xC4] = { _M.optype.CPY , _M.addrmode.ZER , 3 }, -- [2]
[0xC5] = { _M.optype.CMP , _M.addrmode.ZER , 3 }, -- [2]
[0xC6] = { _M.optype.DEC , _M.addrmode.ZER , 5 }, -- [2]
@ -518,7 +518,7 @@ _M.getParam = {
local zprelParam2 = string.unpack("b", string.pack("B", self:readmem(self.pc)))
self.pc = (self.pc + 1) & 0xFFFF
zprelParam2 = zprelParam2 + pc
zprelParam2 = (zprelParam2 + self.pc) & 0xFFFF
return p, zprelParam2
end,
[_M.addrmode.ABI] = function(self)
@ -879,6 +879,7 @@ _M.operations = {
[_M.optype.TSB] = function(self, param)
local m = self:readmem(param)
local v = self.A & m
m = m | self.A
self:writemem(param, m)
if (v == 0) then
self.F = self.F | self.flags.Z
@ -1123,10 +1124,10 @@ _M.operations = {
end,
[_M.optype.BBR] = function(self, param, zprelParam2, m)
-- the bit to test is encoded in the opcode [m].
local btt = 1 << ((m > 4) & 0x07)
local btt = 1 << ((m >> 4) & 0x07)
local v = self:readmem(param) -- zero-page memory location to test
if ((v & btt) == 0x00) then
pc = zprelParam2
self.pc = zprelParam2
end
return 0
end,
@ -1134,7 +1135,7 @@ _M.operations = {
local btt = 1 << ((m >> 4) & 0x07)
local v = self:readmem(param)
if ((v & btt) ~= 0x00) then
pc = zprelParam2
self.pc = zprelParam2
end
return 0
end,