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lips/lips/overrides.lua

329 lines
9.3 KiB
Lua

local insert = table.insert
local path = string.gsub(..., "[^.]+$", "")
local data = require(path.."data")
local overrides = {}
-- note: "self" is an instance of Preproc
local function tob_override(self, name)
-- handle all the addressing modes for lw/sw-like instructions
local dest = self:pop('CPU')
local offset, base
if self:peek('DEREF') then
offset = 0
base = self:pop('DEREF')
elseif self:peek('REG') then
local o = self:pop('CPU')
local b = self:pop('DEREF'):set('tt', 'REG')
self:push_new('ADDU', 'AT', o, b)
offset = 0
base = self:token('DEREF', 'AT')
else -- NUM or LABELSYM
local o = self:pop('CONST')
if self:peek('NUM') then
local temp, err = self:pop('CONST'):compute()
if err then
self:error(err, temp)
end
o:set('offset', temp)
end
offset = self:token(o)
if not o.portion then
offset:set('portion', 'lower')
end
-- attempt to use the fewest possible instructions for this offset
if not o.portion and (o.tt == 'LABELSYM' or o.tok >= 0x80000000) then
local temp = self:token(o):set('portion', 'upperoff')
self:push_new('LUI', 'AT', temp)
if self.s[self.i] ~= nil then
local reg = self:pop('DEREF'):set('tt', 'REG')
if reg.tok ~= 'R0' then
self:push_new('ADDU', 'AT', 'AT', reg)
end
end
base = self:token('DEREF', 'AT')
else
base = self:pop('DEREF')
end
end
self:push_new(name, dest, offset, base)
end
for k, v in pairs(data.instructions) do
if v[2] == 'tob' then
overrides[k] = tob_override
end
end
function overrides:LI(name)
local dest = self:pop('CPU')
local im = self:pop('CONST')
-- for us, this is just semantics. for a "real" assembler,
-- LA could add appropriate RELO LUI/ADDIU directives.
if im.tt == 'LABELSYM' then
self:error('use LA for labels')
end
if im.portion then
-- FIXME: use appropriate instruction based on portion?
self:push_new('ADDIU', dest, 'R0', im)
return
end
im.tok = im.tok % 0x100000000
if im.tok >= 0x10000 and im.tok <= 0xFFFF8000 then
local temp = self:token(im):set('portion', 'upper')
self:push_new('LUI', dest, temp)
if im.tok % 0x10000 ~= 0 then
local temp = self:token(im):set('portion', 'lower')
self:push_new('ORI', dest, dest, temp)
end
elseif im.tok >= 0x8000 and im.tok < 0x10000 then
local temp = self:token(im):set('portion', 'lower')
self:push_new('ORI', dest, 'R0', temp)
else
local temp = self:token(im):set('portion', 'lower')
self:push_new('ADDIU', dest, 'R0', temp)
end
end
function overrides:LA(name)
local dest = self:pop('CPU')
local im = self:pop('CONST')
local im = self:token(im):set('portion', 'upperoff')
self:push_new('LUI', dest, im)
local im = self:token(im):set('portion', 'lower')
self:push_new('ADDIU', dest, dest, im)
end
function overrides:PUSH(name)
local w = name == 'PUSH' and 'SW' or 'LW'
local stack = {}
for _, t in ipairs(self.s) do
if t.tt == 'NUM' then
if t.tok < 0 then
self:error("can't push a negative number of spaces", t.tok)
end
for i=1, t.tok do
insert(stack, '')
end
self:pop()
else
insert(stack, self:pop('CPU'))
end
end
if #stack == 0 then
self:error(name..' requires at least one argument')
end
if name == 'PUSH' then
local im = self:token(#stack*4):set('negate')
self:push_new('ADDIU', 'SP', 'SP', im)
end
for i, r in ipairs(stack) do
if r ~= '' then
local offset = (i - 1)*4
self:push_new(w, r, offset, self:token('DEREF', 'SP'))
end
end
if name == 'JPOP' then
self:push_new('JR', 'RA')
end
if name == 'POP' or name == 'JPOP' then
local im = #stack * 4
self:push_new('ADDIU', 'SP', 'SP', im)
end
end
overrides.POP = overrides.PUSH
overrides.JPOP = overrides.PUSH
function overrides:NAND(name)
local dest = self:pop('CPU')
local src = self:pop('CPU')
local target = self:pop('CPU')
self:push_new('AND', dest, src, target)
self:push_new('NOR', dest, dest, 'R0') -- NOT
end
function overrides:NANDI(name)
local dest = self:pop('CPU')
local src = self:pop('CPU')
local im = self:pop('CONST')
self:push_new('ANDI', dest, src, im)
self:push_new('NOR', dest, dest, 'R0') -- NOT
end
function overrides:NORI(name)
local dest = self:pop('CPU')
local src = self:pop('CPU')
local im = self:pop('CONST')
self:push_new('ORI', dest, src, im)
self:push_new('NOR', dest, dest, 'R0') -- NOT
end
function overrides:ROL(name)
local first = name == 'ROL' and 'SLL' or 'SRL'
local second = name == 'ROL' and 'SRL' or 'SLL'
local dest = self:pop('CPU')
local src = self:pop('CPU')
local im = self:pop('CONST')
if dest == 'AT' or src == 'AT' then
self:error('registers cannot be AT in this pseudo-instruction')
end
self:push_new(first, dest, src, im)
local temp, err = im:compute()
if err then
self:error(err, temp)
end
self:push_new(second, 'AT', src, 32 - temp)
self:push_new('OR', dest, dest, 'AT')
end
overrides.ROR = overrides.ROL
function overrides:ABS(name)
local dest = self:pop('CPU')
local src = self:pop('CPU')
self:push_new('SRA', 'AT', src, 31)
self:push_new('XOR', dest, src, 'AT')
self:push_new('SUBU', dest, dest, 'AT')
end
function overrides:CL(name)
self:expect{'REG'} -- assert there's at least one argument
for i=1, #self.s do
local reg = self:pop('CPU')
self:push_new('CL', reg)
end
end
function overrides:JR(name)
local src = self:peek() and self:pop('CPU') or 'RA'
self:push_new('JR', src)
end
local branch_basics = {
BEQI = 'BEQ',
BGEI = 'BEQ',
BGTI = 'BEQ',
BLEI = 'BNE',
BLTI = 'BNE',
BNEI = 'BNE',
BEQIL = 'BEQL',
BGEIL = 'BEQL',
BGTIL = 'BEQL',
BLEIL = 'BNEL',
BLTIL = 'BNEL',
BNEIL = 'BNEL',
}
function overrides:BLT(name)
local slt = name:sub(#name) == 'U' and 'SLTU' or 'SLT'
local a = self:pop('CPU')
local b = self:pop('CPU')
local offset = self:pop('CONST')
self:push_new(slt, 'AT', a, b)
self:push_new('BNEZ', 'AT', offset)
end
function overrides:BGE(name)
local slt = name:sub(#name) == 'U' and 'SLTU' or 'SLT'
local a = self:pop('CPU')
local b = self:pop('CPU')
local offset = self:pop('CONST')
self:push_new(slt, 'AT', a, b)
self:push_new('BEQZ', 'AT', offset)
end
function overrides:BLE(name)
local slt = name:sub(#name) == 'U' and 'SLTU' or 'SLT'
local a = self:pop('CPU')
local b = self:pop('CPU')
local offset = self:pop('CONST')
self:push_new(slt, 'AT', b, a)
self:push_new('BEQZ', 'AT', offset)
end
function overrides:BGT(name)
local slt = name:sub(#name) == 'U' and 'SLTU' or 'SLT'
local a = self:pop('CPU')
local b = self:pop('CPU')
local offset = self:pop('CONST')
self:push_new(slt, 'AT', b, a)
self:push_new('BNEZ', 'AT', offset)
end
overrides.BLTU = overrides.BLT
overrides.BGEU = overrides.BGE
overrides.BLEU = overrides.BLE
overrides.BGTU = overrides.BGT
function overrides:BEQI(name)
local branch = branch_basics[name]
local reg = self:pop('CPU')
local im = self:pop('CONST')
local offset = self:pop('CONST')
if reg == 'AT' then
self:error('register cannot be AT in this pseudo-instruction')
end
self:push_new('ADDIU', 'AT', 'R0', im)
self:push_new(branch, reg, 'AT', offset)
end
overrides.BNEI = overrides.BEQI
overrides.BEQIL = overrides.BEQI
overrides.BNEIL = overrides.BEQI
function overrides:BLTI(name)
local branch = branch_basics[name]
local reg = self:pop('CPU')
local im = self:pop('CONST')
local offset = self:pop('CONST')
if reg == 'AT' then
self:error('register cannot be AT in this pseudo-instruction')
end
self:push_new('SLTI', 'AT', reg, im)
self:push_new(branch, 'R0', 'AT', offset)
end
overrides.BGEI = overrides.BLTI
overrides.BLTIL = overrides.BLTI
overrides.BGEIL = overrides.BLTI
function overrides:BLEI(name)
-- TODO: this can probably be optimized
if name:sub(#name) == 'L' then
self:error('unimplemented pseudo-instruction', name)
end
local branch = branch_basics[name]
local reg = self:pop('CPU')
local im = self:pop('CONST')
local offset = self:pop('CONST')
if reg == 'AT' then
self:error('register cannot be AT in this pseudo-instruction')
end
self:push_new('ADDIU', 'AT', 'R0', im)
local beq_offset
if name == 'BLEI' or name =='BLEIL' then
beq_offset = offset
else
-- branch to delay slot of the next branch
beq_offset = self:token('NUM', 2):set('fixed')
end
self:push_new('BEQ', reg, 'AT', beq_offset)
self:push_new('SLT', 'AT', reg, 'AT')
self:push_new(branch, 'AT', 'R0', offset)
end
overrides.BGTI = overrides.BLEI
overrides.BLEIL = overrides.BLEI
overrides.BGTIL = overrides.BLEI
return overrides