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Fix a bug in dcpu_skip, add a test program. #15

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Fix a bug in dcpu_skip, add a test program. #15

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4ededcb
My local mods to the Makefile, probably not interesting to anyone else.
Apr 18, 2012
fb0b53b
This test shows a bug on line 92 of dcpu_skip. The conditional there
Apr 18, 2012
368192e
Fix to skip on line 92 of emulator.c. Also hijacked one of the illeg…
Apr 18, 2012
89de205
Reverting my local Makefile changes.
Apr 19, 2012
8b214f5
Fix a bug in dcpu_skip(). The 'b' instruction operand (or 'a' operan…
Apr 20, 2012
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11 changes: 7 additions & 4 deletions emulator.c
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Original file line number Diff line number Diff line change
Expand Up @@ -80,7 +80,7 @@ u16 *dcpu_opr(struct dcpu *d, u16 code) {
}
}

static u8 skiptable[32] = { /* operand forms that advance pc */
static u8 skiptable[64] = { /* operand forms that advance pc */
[0x10] = 1, [0x11] = 1, [0x12] = 1, [0x13] = 1,
[0x14] = 1, [0x15] = 1, [0x16] = 1, [0x17] = 1,
[0x1E] = 1, [0x1F] = 1,
Expand All @@ -89,8 +89,8 @@ static u8 skiptable[32] = { /* operand forms that advance pc */
void dcpu_skip(struct dcpu *d) {
u16 op = d->m[d->pc++];
d->pc += skiptable[op >> 10];
if ((op & 15) == 0)
d->pc += skiptable[(op >> 4) & 31];
if ((op & 15) != 0)
d->pc += skiptable[(op >> 4) & 63];
}

void dcpu_step(struct dcpu *d) {
Expand Down Expand Up @@ -133,8 +133,11 @@ void dcpu_step(struct dcpu *d) {
d->m[--(d->sp)] = d->pc;
d->pc = a;
return;
case 0x3F:
fprintf(stderr, "< ILLEGAL OPCODE (success code)>\n");
exit(0);
default:
fprintf(stderr, "< ILLEGAL OPCODE >\n");
exit(0);
exit(1);
}
}
21 changes: 21 additions & 0 deletions tests/testskip.s
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Original file line number Diff line number Diff line change
@@ -0,0 +1,21 @@
; Skip test. Assumes skipping a 3-word instruction may be faulty, but
; skipping a 2-word instruction works.

SET A, 0x10 ; c001
SET [0x1000], A ; 01e1, 1000
SET [0xEEE0], 0 ; 81e1, eee0
IFN A, 0x10 ; c00d
SET [0x1000], [0xEEE0] ; 79e1, 1000, eee0
SET A, [0x1000] ; 7801, 1000
; A should still be 0x10

IFN A, 0x10 ; c00d
SET PC, fail ; 7dc1, 000f

:pass
WORD 0x3FF0 ; 3ff0

:fail
WORD 0xEEE0 ; eee0


168 changes: 168 additions & 0 deletions tests/testskip3.s
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Original file line number Diff line number Diff line change
@@ -0,0 +1,168 @@
SET A, 0x10

IFN A, 0x10
SUB A, 0
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 1
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 2
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 3
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 4
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 5
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 6
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 7
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 8
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 9
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 10
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 11
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 12
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 13
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 14
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 15
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 16
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 17
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 18
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 19
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 20
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 21
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 22
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 23
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 24
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 25
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 26
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 27
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 28
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 29
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 30
IFN A, 0x10
SET PC, fail

IFN A, 0x10
SUB A, 31
IFN A, 0x10
SET PC, fail

:pass
WORD 0x3FF0

:fail
WORD 0xEEE0