mirrors/cosmopolitan
1
0
Fork 0
mirror of https://github.com/jart/cosmopolitan.git synced 2025-05-28 08:12:28 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 1

Fix bugs and have emulator emulate itself

Browse source
This commit is contained in:
Justine Tunney 2020-08-31 05:17:31 -07:00
parent 5aabacb361
commit bd29223891
111 changed files with 1283 additions and 2073 deletions
Download patch file Download diff file Expand all files Collapse all files

37
tool/build/lib/alu.c
View file

@ -25,8 +25,8 @@
* NexGen32e Arithmetic Unit.
*/
int64_t Alu(int w, int h, uint64_t x, uint64_t y, uint32_t *flags) {
bool zf, sf, c, o, cf;
uint64_t t, z, s, m, k;
bool cf, of, zf, sf, af, carry;
assert(w < 4);
k = 8;
k <<= w;
@ -35,9 +35,10 @@ int64_t Alu(int w, int h, uint64_t x, uint64_t y, uint32_t *flags) {
m = s;
m |= s - 1;
t = x;
c = 0;
o = 0;
cf = GetFlag(*flags, FLAGS_CF);
cf = 0;
of = 0;
af = 0;
carry = GetFlag(*flags, FLAGS_CF);
switch (h & 7) {
case ALU_OR:
z = x | y;
@ -50,22 +51,26 @@ int64_t Alu(int w, int h, uint64_t x, uint64_t y, uint32_t *flags) {
break;
case ALU_CMP:
h |= 8;
cf = 0;
carry = 0;
case ALU_SBB:
t = (x & m) - cf;
c = (x & m) < (t & m);
t = (x & m) - carry;
cf = (x & m) < (t & m);
af = (x & 15) < (t & 15);
case ALU_SUB:
z = (t & m) - (y & m);
c |= (t & m) < (z & m);
o = !!((z ^ x) & (x ^ y) & s);
cf |= (t & m) < (z & m);
af |= (t & 15) < (z & 15);
of = !!((z ^ x) & (x ^ y) & s);
break;
case ALU_ADC:
t = (x & m) + cf;
c = (t & m) < (x & m);
t = (x & m) + carry;
cf = (t & m) < (x & m);
af = (t & 15) < (x & 15);
case ALU_ADD:
z = (t & m) + (y & m);
c |= (z & m) < (y & m);
o = !!((z ^ x) & (z ^ y) & s);
cf |= (z & m) < (y & m);
af |= (z & 15) < (y & 15);
of = !!((z ^ x) & (z ^ y) & s);
break;
default:
unreachable;
@ -73,8 +78,10 @@ int64_t Alu(int w, int h, uint64_t x, uint64_t y, uint32_t *flags) {
z &= m;
zf = !z;
sf = !!(z & s);
*flags &= ~(1 << FLAGS_CF | 1 << FLAGS_ZF | 1 << FLAGS_SF | 1 << FLAGS_OF);
*flags |= c << FLAGS_CF | zf << FLAGS_ZF | sf << FLAGS_SF | o << FLAGS_OF;
*flags = (*flags & ~(1 << FLAGS_CF | 1 << FLAGS_ZF | 1 << FLAGS_SF |
1 << FLAGS_OF | 1 << FLAGS_AF)) |
cf << FLAGS_CF | zf << FLAGS_ZF | sf << FLAGS_SF | of << FLAGS_OF |
af << FLAGS_AF;
*flags = SetLazyParityByte(*flags, x);
if (h & ALU_TEST) z = x;
return z;