usage.md

Usage

Inherit Xbyak_riscv::CodeGenerator class and make the class method.

#include <xbyak_riscv/xbyak_riscv.hpp>

using namespace Xbyak_riscv;

struct Code : CodeGenerator {
  Code(int v)
  {
    addw(a0, a0, a1);
    addiw(a0, a0, v);
    ret();
  }
};

int main()
{
  const int v1 = 5;
  const int v2 = 7;
  const int v3 = 9;
  Code c(v1);
  c.ready();
  auto f = c.getCode<int (*)(int, int)>();
  int v = f(v2, v3);
  printf("%d+%d+%d=%d(%s)\n", v1, v2, v3, v, v == v1 + v2 + v3 ? "ok" : "ng");
}

The constructor of Code class generates a function that takes two integers, x and y, and returns x + y + v. Calling ready() completes the code generation process. c.getCode<int (*)(int,int)>() returns the function pointer and you can use it.

Registers

Register	ABI Name
x0	zero
x1	ra
x2	sp
x3	gp
x4	tp
x5	t0
x6-7	t1-2
x8	s0/fp
x9	s1
x10-11	a0-1
x12-17	a2-7
x18-27	s2-11
x28-31	t3-6

These names are defined in the Xbyak_riscv namespace.

Syntax

asm	Xbyak
add x3, x4, x5	add(x3, x4, x5);
ld x3, 16(x4)	ld(x3, x4, 16);
sw t0,8(s1)	sw(t0, s1, 8);
amoswap.w a0,a1,(a2)	amoswap_w(a0, a1, a2);

Replace a period in instructions with an underscore.

RVC

Use supportRVC() to enable RVC instructions.

Macros

• Define XBYAK_RISCV_V = 1 to enable Vector Operations.