From 9521e26a164eb4689b34d82a5de0d998bdd4c4dc Mon Sep 17 00:00:00 2001
From: Kevin O'Connor <kevin@koconnor.net>
Date: Fri, 4 Jul 2008 13:04:29 -0400
Subject: Extract 'struct bregs' out of biosvar.h; clean up header includes.

---
 src/bregs.h | 90 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 src/bregs.h

(limited to 'src/bregs.h')

diff --git a/src/bregs.h b/src/bregs.h
new file mode 100644
index 0000000..8da6c52
--- /dev/null
+++ b/src/bregs.h
@@ -0,0 +1,90 @@
+// 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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