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A couple of small accuracy improvements #48

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a747d20
prim_ops: Keep top bits when pushing a segment register onto 32-bit s…
lkundrak Feb 28, 2025
f125ec3
prim_ops: Unset AF on SHL by bits != 0
lkundrak Feb 27, 2025
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1 change: 1 addition & 0 deletions include/prim_ops.h
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Original file line number Diff line number Diff line change
Expand Up @@ -130,6 +130,7 @@ void ins (x86emu_t *emu, int size);
void outs (x86emu_t *emu, int size);
void push_word (x86emu_t *emu, u16 w);
void push_long (x86emu_t *emu, u32 w);
void push_halflong (x86emu_t *emu, u16 w);
u16 pop_word (x86emu_t *emu);
u32 pop_long (x86emu_t *emu);
int eval_condition(x86emu_t *emu, unsigned type);
Expand Down
8 changes: 4 additions & 4 deletions ops.c
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Original file line number Diff line number Diff line change
Expand Up @@ -437,7 +437,7 @@ static void x86emuOp_push_ES(x86emu_t *emu, u8 op1)
OP_DECODE("push es");

if(MODE_DATA32) {
push_long(emu, emu->x86.R_ES);
push_halflong(emu, emu->x86.R_ES);
}
else {
push_word(emu, emu->x86.R_ES);
Expand All @@ -464,7 +464,7 @@ static void x86emuOp_push_CS(x86emu_t *emu, u8 op1)
{
OP_DECODE("push cs");
if(MODE_DATA32) {
push_long(emu, emu->x86.R_CS);
push_halflong(emu, emu->x86.R_CS);
}
else {
push_word(emu, emu->x86.R_CS);
Expand Down Expand Up @@ -493,7 +493,7 @@ static void x86emuOp_push_SS(x86emu_t *emu, u8 op1)
OP_DECODE("push ss");

if(MODE_DATA32) {
push_long(emu, emu->x86.R_SS);
push_halflong(emu, emu->x86.R_SS);
}
else {
push_word(emu, emu->x86.R_SS);
Expand Down Expand Up @@ -521,7 +521,7 @@ static void x86emuOp_push_DS(x86emu_t *emu, u8 op1)
OP_DECODE("push ds");

if(MODE_DATA32) {
push_long(emu, emu->x86.R_DS);
push_halflong(emu, emu->x86.R_DS);
}
else {
push_word(emu, emu->x86.R_DS);
Expand Down
22 changes: 22 additions & 0 deletions prim_ops.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1262,6 +1262,7 @@ u8 shl_byte(x86emu_t *emu, u8 d, u8 s)
CONDITIONAL_SET_FLAG((res & 0xff) == 0, F_ZF);
CONDITIONAL_SET_FLAG(res & 0x80, F_SF);
CONDITIONAL_SET_FLAG(PARITY(res & 0xff), F_PF);
CLEAR_FLAG(F_AF);
} else {
res = (u8) d;
}
Expand All @@ -1281,6 +1282,7 @@ u8 shl_byte(x86emu_t *emu, u8 d, u8 s)
CONDITIONAL_SET_FLAG((d << (s-1)) & 0x80, F_CF);
CLEAR_FLAG(F_OF);
CLEAR_FLAG(F_SF);
CLEAR_FLAG(F_AF);
SET_FLAG(F_PF);
SET_FLAG(F_ZF);
}
Expand All @@ -1304,6 +1306,7 @@ u16 shl_word(x86emu_t *emu, u16 d, u8 s)
CONDITIONAL_SET_FLAG((res & 0xffff) == 0, F_ZF);
CONDITIONAL_SET_FLAG(res & 0x8000, F_SF);
CONDITIONAL_SET_FLAG(PARITY(res & 0xff), F_PF);
CLEAR_FLAG(F_AF);
} else {
res = (u16) d;
}
Expand All @@ -1321,6 +1324,7 @@ u16 shl_word(x86emu_t *emu, u16 d, u8 s)
CONDITIONAL_SET_FLAG((d << (s-1)) & 0x8000, F_CF);
CLEAR_FLAG(F_OF);
CLEAR_FLAG(F_SF);
CLEAR_FLAG(F_AF);
SET_FLAG(F_PF);
SET_FLAG(F_ZF);
}
Expand All @@ -1344,6 +1348,7 @@ u32 shl_long(x86emu_t *emu, u32 d, u8 s)
CONDITIONAL_SET_FLAG((res & 0xffffffff) == 0, F_ZF);
CONDITIONAL_SET_FLAG(res & 0x80000000, F_SF);
CONDITIONAL_SET_FLAG(PARITY(res & 0xff), F_PF);
CLEAR_FLAG(F_AF);
} else {
res = d;
}
Expand All @@ -1358,6 +1363,7 @@ u32 shl_long(x86emu_t *emu, u32 d, u8 s)
CONDITIONAL_SET_FLAG((d << (s-1)) & 0x80000000, F_CF);
CLEAR_FLAG(F_OF);
CLEAR_FLAG(F_SF);
CLEAR_FLAG(F_AF);
SET_FLAG(F_PF);
SET_FLAG(F_ZF);
}
Expand Down Expand Up @@ -2515,6 +2521,22 @@ void push_long(x86emu_t *emu, u32 w)
}
}

/****************************************************************************
REMARKS:
Pushes a 16-bit (segment) register onto the 32-bit data stack.
****************************************************************************/
void push_halflong(x86emu_t *emu, u16 w)
{
if(MODE_STACK32) {
emu->x86.R_ESP -= 4;
store_data_word_abs(emu, emu->x86.seg + R_SS_INDEX, emu->x86.R_ESP, w);
}
else {
emu->x86.R_SP -= 4;
store_data_word_abs(emu, emu->x86.seg + R_SS_INDEX, emu->x86.R_SP, w);
}
}

/****************************************************************************
REMARKS:
Pops a word from the stack.
Expand Down
2 changes: 1 addition & 1 deletion test/0034_ret_far_32.done
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@
; 0 1 2 3 4 5 6 7 8 9 a b c d e f
00001000: 68 aa aa aa aa 0e e8 06 00 00 00 68 bb bb bb bb
00001010: f4 ca 04 00 90 90 f4
fffffff0: 0b 00 00 00 00 01 00 00 bb bb bb bb
fffffff0: 0b 00 00 00 00 01 * * bb bb bb bb

; - - registers
msr[0010] 0000000000000006 ; tsc
Expand Down
27 changes: 27 additions & 0 deletions test/0039_shl.done
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Original file line number Diff line number Diff line change
@@ -0,0 +1,27 @@
; - - memory
; 0 1 2 3 4 5 6 7 8 9 a b c d e f
00001000: 9c 66 c1 e1 00 9c 66 d1 e1 9c f4
0000fff0: 83 00 12 00 12 00

; - - registers
msr[0010] 0000000000000006 ; tsc

cr0=00000000 cr1=00000000 cr2=00000000 cr3=00000000 cr4=00000000
dr0=00000000 dr1=00000000 dr2=00000000 dr3=00000000 dr6=00000000 dr7=00000000

gdt.base=00000000 gdt.limit=ffff
idt.base=00000000 idt.limit=ffff
tr=0000 tr.base=00000000 tr.limit=00000000 tr.acc=0000
ldt=0000 ldt.base=00000000 ldt.limit=00000000 ldt.acc=0000

cs=0100 cs.base=00001000 cs.limit=0000ffff cs.acc=009b
ss=0000 ss.base=00000000 ss.limit=0000ffff ss.acc=0093
ds=0000 ds.base=00000000 ds.limit=0000ffff ds.acc=0093
es=0000 es.base=00000000 es.limit=0000ffff es.acc=0093
fs=0000 fs.base=00000000 fs.limit=0000ffff fs.acc=0093
gs=0000 gs.base=00000000 gs.limit=0000ffff gs.acc=0093

eax=00000000 ebx=00000000 ecx=fffffffe edx=00000000
esi=00000000 edi=00000000 ebp=00000000 esp=0000fffa
eip=0000000b eflags=00000081 ; sf cf

11 changes: 11 additions & 0 deletions test/0039_shl.tst
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Original file line number Diff line number Diff line change
@@ -0,0 +1,11 @@
[init]

ecx=0xffffffff eflags=0x00000010

[code start=0x100:0x0]

pushf
shl ecx,0
pushf
shl ecx,1
pushf
29 changes: 29 additions & 0 deletions test/0040_pushseg.done
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Original file line number Diff line number Diff line change
@@ -0,0 +1,29 @@
; - - memory
; 0 1 2 3 4 5 6 7 8 9 a b c d e f
00001000: 68 78 56 34 12 58 16 1f 1e 58 f4
00002000: 00 00 00 00 00 00 00 00 ff ff 00 10 00 93 40 00
00002010: ff ff 00 00 00 93 cf 00
fffffff0: 10 00 34 12

; - - registers
msr[0010] 0000000000000007 ; tsc

cr0=00000001 cr1=00000000 cr2=00000000 cr3=00000000 cr4=00000000
dr0=00000000 dr1=00000000 dr2=00000000 dr3=00000000 dr6=00000000 dr7=00000000

gdt.base=00002000 gdt.limit=ffff
idt.base=00000000 idt.limit=ffff
tr=0000 tr.base=00000000 tr.limit=00000000 tr.acc=0000
ldt=0000 ldt.base=00000000 ldt.limit=00000000 ldt.acc=0000

cs=0008 cs.base=00001000 cs.limit=0000ffff cs.acc=0493
ss=0010 ss.base=00000000 ss.limit=ffffffff ss.acc=0c93
ds=0010 ds.base=00000000 ds.limit=ffffffff ds.acc=0c93
es=0000 es.base=00000000 es.limit=00000000 es.acc=0000
fs=0000 fs.base=00000000 fs.limit=00000000 fs.acc=0000
gs=0000 gs.base=00000000 gs.limit=00000000 gs.acc=0000

eax=12340010 ebx=00000000 ecx=00000000 edx=00000000
esi=00000000 edi=00000000 ebp=00000000 esp=00000000
eip=0000000b eflags=00000002

17 changes: 17 additions & 0 deletions test/0040_pushseg.tst
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Original file line number Diff line number Diff line change
@@ -0,0 +1,17 @@
[init mode=protected]

gdt.base=0x2000
gdt[0x00]=0
gdt[0x08]=descr(base=0x1000,limit=0xffff,acc=0x493)
gdt[0x10]=descr(base=0,limit=0xffffffff,acc=0xc93)

ss=0x10

[code start=8:0 bits=32]

push 0x12345678
pop eax
push ss
pop ds
push ds
pop eax