mirror of https://github.com/notwa/lips
reimplement branch pseudos, remove branch-immediates for now
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51820234a8
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@ -205,6 +205,15 @@ function overrides:JR(name)
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end
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local branch_basics = {
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BGE = 'BEQ',
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BLE = 'BEQ',
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BLT = 'BNE',
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BGT = 'BNE',
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BGEL = 'BEQL',
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BLEL = 'BEQL',
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BLTL = 'BNEL',
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BGTL = 'BNEL',
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BEQI = 'BEQ',
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BGEI = 'BEQ',
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BGTI = 'BEQ',
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@ -221,108 +230,40 @@ local branch_basics = {
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function overrides:BLT(name)
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local slt = name:sub(#name) == 'U' and 'SLTU' or 'SLT'
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local branch = branch_basics[name:sub(1, 3)]
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local a = self:pop('CPU')
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local b = self:pop('CPU')
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local offset = self:pop('CONST')
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self:push_new(slt, 'AT', a, b)
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self:push_new('BNEZ', 'AT', offset)
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end
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function overrides:BGE(name)
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local slt = name:sub(#name) == 'U' and 'SLTU' or 'SLT'
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local a = self:pop('CPU')
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local b = self:pop('CPU')
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local offset = self:pop('CONST')
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self:push_new(slt, 'AT', a, b)
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self:push_new('BEQZ', 'AT', offset)
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end
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function overrides:BLE(name)
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local slt = name:sub(#name) == 'U' and 'SLTU' or 'SLT'
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local a = self:pop('CPU')
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local b = self:pop('CPU')
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local offset = self:pop('CONST')
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self:push_new(slt, 'AT', b, a)
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self:push_new('BEQZ', 'AT', offset)
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end
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function overrides:BGT(name)
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local slt = name:sub(#name) == 'U' and 'SLTU' or 'SLT'
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local a = self:pop('CPU')
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local b = self:pop('CPU')
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local offset = self:pop('CONST')
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self:push_new(slt, 'AT', b, a)
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self:push_new('BNEZ', 'AT', offset)
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end
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overrides.BLTU = overrides.BLT
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overrides.BGEU = overrides.BGE
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overrides.BLEU = overrides.BLE
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overrides.BGTU = overrides.BGT
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function overrides:BEQI(name)
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local branch = branch_basics[name]
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local reg = self:pop('CPU')
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local im = self:pop('CONST')
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local offset = self:pop('CONST')
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if reg == 'AT' then
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self:error('register cannot be AT in this pseudo-instruction')
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end
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self:push_new('ADDIU', 'AT', 'R0', im)
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self:push_new(branch, reg, 'AT', offset)
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end
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overrides.BNEI = overrides.BEQI
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overrides.BEQIL = overrides.BEQI
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overrides.BNEIL = overrides.BEQI
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function overrides:BLTI(name)
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local branch = branch_basics[name]
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local reg = self:pop('CPU')
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local im = self:pop('CONST')
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local offset = self:pop('CONST')
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if reg == 'AT' then
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self:error('register cannot be AT in this pseudo-instruction')
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end
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self:push_new('SLTI', 'AT', reg, im)
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self:push_new(branch, 'R0', 'AT', offset)
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end
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overrides.BGEI = overrides.BLTI
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overrides.BLTIL = overrides.BLTI
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overrides.BGEIL = overrides.BLTI
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function overrides:BLEI(name)
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-- TODO: this can probably be optimized
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if name:sub(#name) == 'L' then
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self:error('unimplemented pseudo-instruction', name)
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end
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local branch = branch_basics[name]
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local reg = self:pop('CPU')
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local im = self:pop('CONST')
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local offset = self:pop('CONST')
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if reg == 'AT' then
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self:error('register cannot be AT in this pseudo-instruction')
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end
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self:push_new('ADDIU', 'AT', 'R0', im)
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local beq_offset
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if name == 'BLEI' or name =='BLEIL' then
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beq_offset = offset
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else
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-- branch to delay slot of the next branch
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beq_offset = self:token('NUM', 2):set('fixed')
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end
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self:push_new('BEQ', reg, 'AT', beq_offset)
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self:push_new('SLT', 'AT', reg, 'AT')
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self:push_new(branch, 'AT', 'R0', offset)
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end
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overrides.BGTI = overrides.BLEI
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overrides.BLEIL = overrides.BLEI
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overrides.BGTIL = overrides.BLEI
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function overrides:BLE(name)
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local slt = name:sub(#name) == 'U' and 'SLTU' or 'SLT'
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local branch = branch_basics[name:sub(1, 3)]
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local a = self:pop('CPU')
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local b = self:pop('CPU')
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local offset = self:pop('CONST')
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self:push_new(slt, 'AT', b, a)
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self:push_new(branch, 'AT', 'R0', offset)
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end
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overrides.BGE = overrides.BLT
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overrides.BGT = overrides.BLE
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overrides.BGEL = overrides.BLT
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overrides.BGTL = overrides.BLE
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overrides.BLEL = overrides.BLE
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overrides.BLTL = overrides.BLT
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overrides.BGEU = overrides.BLT
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overrides.BGTU = overrides.BLE
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overrides.BLEU = overrides.BLE
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overrides.BLTU = overrides.BLT
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overrides.BGEUL = overrides.BLT
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overrides.BGTUL = overrides.BLE
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overrides.BLEUL = overrides.BLE
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overrides.BLTUL = overrides.BLT
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return overrides
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