pineapple-src/externals/xbyak/sample/jmp_table.cpp

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2020-12-28 15:15:37 +00:00
/*
sample of move(reg, LABEL);, L(LABEL), putL(LABEL);
*/
#include <stdio.h>
#define XBYAK_NO_OP_NAMES
#include <xbyak/xbyak.h>
const int expectTbl[] = {
5, 9, 12
};
struct Code : Xbyak::CodeGenerator {
explicit Code(int mode, size_t size, void *p)
: Xbyak::CodeGenerator(size, p)
{
inLocalLabel();
#ifdef XBYAK64
const Xbyak::Reg64& a = rax;
const Xbyak::Reg64& c = rcx;
#ifdef XBYAK64_WIN
mov(rax, rcx);
#else
mov(rax, rdi);
#endif
#else
const Xbyak::Reg32& a = eax;
const Xbyak::Reg32& c = ecx;
mov(a, ptr [esp + 4]);
#endif
switch (mode) {
case 0:
mov(c, ".jmp_table");
lea(c, ptr [c + a * 8]);
jmp(c);
align(8);
L(".jmp_table");
mov(a, expectTbl[0]);
ret();
align(8);
mov(a, expectTbl[1]);
ret();
align(8);
mov(a, expectTbl[2]);
ret();
break;
case 1:
/*
the label for putL is defined when called
*/
mov(c, ".jmp_table");
jmp(ptr [c + a * (int)sizeof(size_t)]);
L(".label1");
mov(a, expectTbl[0]);
jmp(".end");
L(".label2");
mov(a, expectTbl[1]);
jmp(".end");
L(".label3");
mov(a, expectTbl[2]);
jmp(".end");
L(".end");
ret();
ud2();
align(8);
L(".jmp_table");
putL(".label1");
putL(".label2");
putL(".label3");
break;
case 2:
/*
the label for putL is not defined when called
*/
jmp(".in");
ud2();
align(8);
L(".jmp_table");
putL(".label1");
putL(".label2");
putL(".label3");
L(".in");
mov(c, ".jmp_table");
jmp(ptr [c + a * (int)sizeof(size_t)]);
L(".label1");
mov(a, expectTbl[0]);
jmp(".end");
L(".label2");
mov(a, expectTbl[1]);
jmp(".end");
L(".label3");
mov(a, expectTbl[2]);
jmp(".end");
L(".end");
ret();
break;
}
outLocalLabel();
}
};
int main()
try
{
for (int mode = 0; mode < 3; mode++) {
printf("mode=%d\n", mode);
for (int grow = 0; grow < 2; grow++) {
printf("auto grow=%s\n", grow ? "on" : "off");
Code c(mode, grow ? 30 : 4096, grow ? Xbyak::AutoGrow : 0);
int (*f)(int) = c.getCode<int (*)(int)>();
c.ready();
for (int i = 0; i < 3; i++) {
const int a = expectTbl[i];
const int b = f(i);
if (a != b) {
printf("ERR i=%d, a=%d, b=%d\n", i, a, b);
exit(1);
}
}
}
}
puts("ok");
} catch (std::exception& e) {
printf("ERR %s\n", e.what());
}