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X86: Make signed multiplication do something different from unsigned.

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--HG--
extra : convert_revision : 333c4a3464d708d4d8cea88931259ab96c2f75ed
This commit is contained in:
Gabe Black 2007-09-06 16:25:29 -07:00
parent 5052e2cb10
commit 7f079149f1
2 changed files with 33 additions and 9 deletions
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6
src/arch/x86/isa/insts/arithmetic/multiply_and_divide.py
View file

@ -134,7 +134,7 @@ def macroop IMUL_B_P
def macroop IMUL_R
{
muleh t1, rax, reg
mulehs t1, rax, reg
mulel rax, rax, reg
mov rdx, rdx, t1
};
@ -142,7 +142,7 @@ def macroop IMUL_R
def macroop IMUL_M
{
ld t1, seg, sib, disp
muleh rdx, rax, t1
mulehs rdx, rax, t1
mulel rax, rax, t1
};
@ -150,7 +150,7 @@ def macroop IMUL_P
{
rdip t7
ld t1, seg, riprel, disp
muleh rdx, rax, t1
mulehs rdx, rax, t1
mulel rax, rax, t1
};

36
src/arch/x86/isa/microops/regop.isa
View file

@ -258,13 +258,18 @@ let {{
# If op2 is used anywhere, make register and immediate versions
# of this code.
matcher = re.compile("op2(?P<typeQual>\\.\\w+)?")
if matcher.search(allCode):
matcher = re.compile("(?<!\\w)(?P<prefix>s?)op2(?P<typeQual>\\.\\w+)?")
match = matcher.search(allCode)
if match:
typeQual = ""
if match.group("typeQual"):
typeQual = match.group("typeQual")
src2_name = "%spsrc2%s" % (match.group("prefix"), typeQual)
self.buildCppClasses(name, Name, suffix,
matcher.sub("psrc2", code),
matcher.sub("psrc2", flag_code),
matcher.sub("psrc2", cond_check),
matcher.sub("psrc2", else_code))
matcher.sub(src2_name, code),
matcher.sub(src2_name, flag_code),
matcher.sub(src2_name, cond_check),
matcher.sub(src2_name, else_code))
self.buildCppClasses(name + "i", Name, suffix + "Imm",
matcher.sub("imm8", code),
matcher.sub("imm8", flag_code),
@ -462,6 +467,11 @@ let {{
class Mulel(FlagRegOp):
code = 'DestReg = merge(DestReg, psrc1 * op2, dataSize);'
# Neither of these is quite correct because it assumes that right shifting
# a signed or unsigned value does sign or zero extension respectively.
# The C standard says that what happens on a right shift with a 1 in the
# MSB position is undefined. On x86 and under likely most compilers the
# "right thing" happens, but this isn't a guarantee.
class Muleh(FlagRegOp):
code = '''
int halfSize = (dataSize * 8) / 2;
@ -476,6 +486,20 @@ let {{
DestReg = merge(DestReg, result, dataSize);
'''
class Mulehs(FlagRegOp):
code = '''
int halfSize = (dataSize * 8) / 2;
int64_t spsrc1_h = spsrc1 >> halfSize;
int64_t spsrc1_l = spsrc1 & mask(halfSize);
int64_t spsrc2_h = sop2 >> halfSize;
int64_t spsrc2_l = sop2 & mask(halfSize);
int64_t result =
((spsrc1_l * spsrc2_h + spsrc1_h * spsrc2_l +
((spsrc1_l * spsrc2_l) >> halfSize)) >> halfSize) +
spsrc1_h * spsrc2_h;
DestReg = merge(DestReg, result, dataSize);
'''
class Div1(FlagRegOp):
code = '''
int halfSize = (dataSize * 8) / 2;