})
char **environ __attribute__((weak));
+const unsigned long *_auxv __attribute__((weak));
/* startup code */
void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) _start(void)
"slli a2, a0, "PTRLOG"\n" // envp (a2) = SZREG*argc ...
"add a2, a2, "SZREG"\n" // + SZREG (skip null)
"add a2,a2,a1\n" // + argv
+
+ "add a3, a2, zero\n" // iterate a3 over envp to find auxv (after NULL)
+ "0:\n" // do {
+ "ld a4, 0(a3)\n" // a4 = *a3;
+ "add a3, a3, "SZREG"\n" // a3 += sizeof(void*);
+ "bne a4, zero, 0b\n" // } while (a4);
+ "lui a4, %hi(_auxv)\n" // a4 = &_auxv (high bits)
+ "sd a3, %lo(_auxv)(a4)\n" // store a3 into _auxv
+
"lui a3, %hi(environ)\n" // a3 = &environ (high bits)
"sd a2,%lo(environ)(a3)\n" // store envp(a2) into environ
"andi sp,a1,-16\n" // sp must be 16-byte aligned