<div dir="ltr"><div style="color:rgb(0,0,0);font-family:Arial;font-size:14px;font-variant-numeric:normal;font-variant-east-asian:normal;line-height:23.8px;margin:0px">Hi all:</div><div style="color:rgb(0,0,0);font-family:Arial;font-size:14px;font-variant-numeric:normal;font-variant-east-asian:normal;line-height:23.8px;margin:0px"><br></div><div style="color:rgb(0,0,0);font-family:Arial;font-size:14px;font-variant-numeric:normal;font-variant-east-asian:normal;line-height:23.8px;margin:0px">I am very interested in the implementation of foreign api.</div><div style="color:rgb(0,0,0);font-family:Arial;font-size:14px;font-variant-numeric:normal;font-variant-east-asian:normal;line-height:23.8px;margin:0px">While reading the code, I have some questions about the code related to the architecture.<span class="gmail-Apple-converted-space"> </span><br>For example, in file src/java.base/share/classes/jdk/internal/foreign/abi/x64/X86_64Architecture.java<span class="gmail-Apple-converted-space"> </span><br>private static final int VECTOR_REG_SIZE = 16; // size of XMM register<span class="gmail-Apple-converted-space"> </span><br>VECTOR_REG_SIZE is assigned 16 bytes, 256-bit vectors and 512-bit vectors also exist for x86.<span class="gmail-Apple-converted-space"> </span><br>So I don't quite understand why VECTOR_REG_SIZE is assigned to 16 bytes,</div><div style="color:rgb(0,0,0);font-family:Arial;font-size:14px;font-variant-numeric:normal;font-variant-east-asian:normal;line-height:23.8px;margin:0px">instead of 16 bytes, 32 bytes or 64 bytes depending on the vector type.<span class="gmail-Apple-converted-space"> </span><br>At the same time, in file cpu/x86/foreignGlobals_x86_64.cpp</div><div style="color:rgb(0,0,0);font-family:Arial;font-size:14px;font-variant-numeric:normal;font-variant-east-asian:normal;line-height:23.8px;margin:0px"><div style="margin:0px">int RegSpiller::pd_reg_size(VMReg reg) {</div><div style="margin:0px">  if (reg->is_Register()) {</div><div style="margin:0px">    return 8;</div><div style="margin:0px">  } else if (reg->is_XMMRegister()) {</div><div style="margin:0px">    return 16; </div><div style="margin:0px">  }</div><div style="margin:0px">  return 0; // stack and BAD</div><div style="margin:0px">}</div><div style="margin:0px">Is the 16 returned by RegSpiller::pd_reg_size set according to the value of VECTOR_REG_SIZE?</div><div style="margin:0px"><br></div>Looking forward to your reply.<span class="gmail-Apple-converted-space"> </span><br>Thanks </div></div>