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// Structure layout of cpu registers the the bios uses.
//
// Copyright (C) 2008 Kevin O'Connor <kevin@koconnor.net>
//
// This file may be distributed under the terms of the GNU GPLv3 license.
#ifndef __BREGS_H
#define __BREGS_H
/****************************************************************
* Registers saved/restored in romlayout.S
****************************************************************/
#define UREG(ER, R, RH, RL) union { u32 ER; struct { u16 R; u16 R ## _hi; }; struct { u8 RL; u8 RH; u8 R ## _hilo; u8 R ## _hihi; }; }
// Layout of registers passed in to irq handlers. Note that this
// layout corresponds to code in romlayout.S - don't change it here
// without also updating the assembler code.
struct bregs {
u16 ds;
u16 es;
UREG(edi, di, di_hi, di_lo);
UREG(esi, si, si_hi, si_lo);
UREG(ebx, bx, bh, bl);
UREG(edx, dx, dh, dl);
UREG(ecx, cx, ch, cl);
UREG(eax, ax, ah, al);
u16 ip;
u16 cs;
u16 flags;
} PACKED;
/****************************************************************
* Helper functions
****************************************************************/
// bregs flags bitdefs
#define F_ZF (1<<6)
#define F_CF (1<<0)
static inline void
set_cf(struct bregs *regs, int cond)
{
if (cond)
regs->flags |= F_CF;
else
regs->flags &= ~F_CF;
}
// Frequently used return codes
#define RET_EUNSUPPORTED 0x86
static inline void
set_success(struct bregs *regs)
{
set_cf(regs, 0);
}
static inline void
set_code_success(struct bregs *regs)
{
regs->ah = 0;
set_cf(regs, 0);
}
static inline void
set_fail_silent(struct bregs *regs)
{
set_cf(regs, 1);
}
static inline void
set_code_fail_silent(struct bregs *regs, u8 code)
{
regs->ah = code;
set_cf(regs, 1);
}
#define set_fail(regs) \
__set_fail(__func__, (regs))
#define set_code_fail(regs, code) \
__set_code_fail(__func__, (regs), (code))
// util.c
void __set_fail(const char *fname, struct bregs *regs);
void __set_code_fail(const char *fname, struct bregs *regs, u8 code);
#endif // bregs.h
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