1 /* ----------------------------------------------------------------------- * 2 * 3 * Copyright 2009-2010 Intel Corporation; author: H. Peter Anvin 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, 8 * Boston MA 02110-1301, USA; either version 2 of the License, or 9 * (at your option) any later version; incorporated herein by reference. 10 * 11 * ----------------------------------------------------------------------- */ 12 13 /* 14 * call16.c 15 * 16 * Simple wrapper to call 16-bit core functions from 32-bit code 17 */ 18 19 #include <stddef.h> 20 #include <stdio.h> 21 #include "core.h" 22 23 __export const com32sys_t zero_regs; /* Common all-zero register set */ 24 25 static inline uint32_t eflags(void) 26 { 27 //uint32_t v; 28 29 #if __SIZEOF_POINTER__ == 4 30 uint32_t v; 31 asm volatile("pushfl ; popl %0" : "=rm" (v)); 32 #elif __SIZEOF_POINTER__ == 8 33 uint64_t v; 34 asm volatile("pushfq ; pop %0" : "=rm" (v)); 35 #else 36 #error "Unable to build for to-be-defined architecture type" 37 #endif 38 return v; 39 } 40 41 __export void call16(void (*func)(void), const com32sys_t *ireg, 42 com32sys_t *oreg) 43 { 44 com32sys_t xreg = *ireg; 45 46 /* Enable interrupts if and only if they are enabled in the caller */ 47 xreg.eflags.l = (xreg.eflags.l & ~EFLAGS_IF) | (eflags() & EFLAGS_IF); 48 49 core_farcall((size_t)func, &xreg, oreg); 50 } 51
