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unallow labels as immediates; allow labels in DEREF instructions

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Connor Olding 2015-11-25 21:55:45 -08:00
parent c7f0d15910
commit 82af3d531e
1 changed files with 27 additions and 26 deletions
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53
lips.lua
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@ -111,11 +111,9 @@ local instructions = {
o: constant for offset
b: register to dereference for base
r: relative constant or label for offset
i: immediate (must fit in a halfword)
I: constant or label for index (long jump)
j: (unused) immediate (uses lower halfword)
J: (unused) immediate (uses upper halfword)
k: immediate to negate (must fit in a halfword)
i: immediate (must fit in a halfword; cannot be a label)
k: immediate to negate (must fit in a halfword; cannot be a label)
output format guide:
such and such: writes ... at this position
@ -128,7 +126,7 @@ local instructions = {
T: ft
o: offset
b: base
i: immediate (infmt 'i', 'j', 'J', and 'k' all write to here)
i: immediate (infmt 'i' and 'k' both write to here)
I: index
C: constant (given in argument immediately after)
F: format constant (given in argument after constant)
@ -809,10 +807,13 @@ function Parser:deref()
return reg
end
function Parser:const(relative)
function Parser:const(relative, no_label)
if self.tt ~= 'NUM' and self.tt ~= 'LABELSYM' then
self:error('expected constant')
end
if no_label and self.tt == 'LABELSYM' then
self:error('labels are not allowed here')
end
if relative and self.tt == 'LABELSYM' then
self.tt = 'LABELREL'
end
@ -839,17 +840,13 @@ function Parser:format_in(informat)
elseif c == 'T' and not args.ft then
args.ft = self:register(fpu_registers)
elseif c == 'o' and not args.offset then
args.offset = {'LOWER', self:const()}
args.offset = self:const()
elseif c == 'r' and not args.offset then
args.offset = {'LOWER', self:const('relative')}
args.offset = self:const('relative')
elseif c == 'i' and not args.immediate then
args.immediate = self:const()
args.immediate = self:const(nil, 'no label')
elseif c == 'I' and not args.index then
args.index = {'INDEX', self:const()}
elseif c == 'j' and not args.immediate then
args.immediate = {'LOWER', self:const()}
elseif c == 'J' and not args.immediate then
args.immediate = {'UPPER', self:const()}
elseif c == 'k' and not args.immediate then
args.immediate = {'NEGATE', self:const()}
elseif c == 'b' and not args.base then
@ -857,7 +854,7 @@ function Parser:format_in(informat)
else
error('Internal Error: invalid input formatting string', 1)
end
if c2:find('[dstDSToiIjJkr]') then
if c2:find('[dstDSTorIik]') then
self:optional_comma()
end
end
@ -1002,7 +999,7 @@ function Parser:instruction()
args.immediate = self:const()
args.rd = left
if args.rd == 'AT' or args.rt == 'AT' then
self:error('registers cannot be AT in a pseudo-instruction that uses AT')
self:error('registers cannot be AT in this pseudo-instruction')
end
if args.rd == args.rt and args.rd ~= 'R0' then
self:error('registers cannot be the same')
@ -1054,23 +1051,18 @@ function Parser:instruction()
args.rt = self:register()
self:optional_comma()
local o = self:const()
if o[1] == 'LABELSYM' then
self:error('unimplemented: label as an offset')
end
local is_label = o[1] == 'LABELSYM'
if self:is_EOL() then
local upper = math.floor(o[2]/0x10000)
local lower = o[2] % 0x10000
if lower >= 0x8000 then
-- accommodate for offsets being signed
upper = (upper + 1) % 0x10000
end
local lui_args = {}
lui_args.immediate = {'NUM', upper}
lui_args.immediate = {'UPPEROFF', o}
lui_args.rt = 'AT'
self:format_out(lui[3], lui[1], lui_args, lui[4], lui[5])
args.offset = {'NUM', lower}
args.offset = {'LOWER', o}
args.base = 'AT'
else
if is_label then
self:error('labels cannot be used as offsets')
end
args.offset = o
self:optional_comma()
args.base = self:deref()
@ -1301,6 +1293,15 @@ function Dumper:toval(tok)
elseif tok[1] == 'LOWER' then
local val = self:desym(tok[2])
return val % 0x10000
elseif tok[1] == 'UPPEROFF' then
local val = self:desym(tok[2])
local upper = math.floor(val/0x10000)
local lower = val % 0x10000
if lower >= 0x8000 then
-- accommodate for offsets being signed
upper = (upper + 1) % 0x10000
end
return upper
elseif tok[1] == 'NEGATE' then
local val = -self:desym(tok[2])
return val % 0x10000