Move variables from assembler to C code.

Define macro VAR16FIXED for declaring a variable at a fixed location.
Introduce new file src/misc.c, and move non int15 calls from system.c
    to it.
Implement all fixed location variables in C code.
Move IDT/GDT defs to misc.c.  Remove unused gdt entry 1.

1 files changed, 193 insertions, 0 deletions

diff --git a/src/misc.c b/src/misc.c
new file mode 100644
index 0000000..0c5f608
--- /dev/null
+++ b/src/misc.c
@@ -0,0 +1,193 @@
+// Code for misc 16bit handlers and variables.
+//
+// Copyright (C) 2008  Kevin O'Connor <kevin@koconnor.net>
+// Copyright (C) 2002  MandrakeSoft S.A.
+//
+// This file may be distributed under the terms of the GNU LGPLv3 license.
+
+#include "bregs.h" // struct bregs
+#include "biosvar.h" // GET_BDA
+#include "util.h" // debug_enter
+#include "pic.h" // enable_hwirq
+
+// Amount of continuous ram under 4Gig
+u32 RamSize VAR16_32;
+// Amount of continuous ram >4Gig
+u64 RamSizeOver4G;
+
+
+/****************************************************************
+ * Misc 16bit ISRs
+ ****************************************************************/
+
+// INT 12h Memory Size Service Entry Point
+void VISIBLE16
+handle_12(struct bregs *regs)
+{
+    debug_enter(regs, DEBUG_HDL_12);
+    regs->ax = GET_BDA(mem_size_kb);
+}
+
+// INT 11h Equipment List Service Entry Point
+void VISIBLE16
+handle_11(struct bregs *regs)
+{
+    debug_enter(regs, DEBUG_HDL_11);
+    regs->ax = GET_BDA(equipment_list_flags);
+}
+
+// INT 05h Print Screen Service Entry Point
+void VISIBLE16
+handle_05(struct bregs *regs)
+{
+    debug_enter(regs, DEBUG_HDL_05);
+}
+
+// INT 10h Video Support Service Entry Point
+void VISIBLE16
+handle_10(struct bregs *regs)
+{
+    debug_enter(regs, DEBUG_HDL_10);
+    // dont do anything, since the VGA BIOS handles int10h requests
+}
+
+void VISIBLE16
+handle_nmi()
+{
+    debug_isr(DEBUG_ISR_nmi);
+    BX_PANIC("NMI Handler called\n");
+}
+
+void
+mathcp_setup()
+{
+    dprintf(3, "math cp init\n");
+    // 80x87 coprocessor installed
+    SETBITS_BDA(equipment_list_flags, 0x02);
+    enable_hwirq(13, entry_75);
+}
+
+// INT 75 - IRQ13 - MATH COPROCESSOR EXCEPTION
+void VISIBLE16
+handle_75()
+{
+    debug_isr(DEBUG_ISR_75);
+
+    // clear irq13
+    outb(0, PORT_MATH_CLEAR);
+    // clear interrupt
+    eoi_pic2();
+    // legacy nmi call
+    u32 eax=0, flags;
+    call16_simpint(0x02, &eax, &flags);
+}
+
+
+/****************************************************************
+ * BIOS_CONFIG_TABLE
+ ****************************************************************/
+
+// DMA channel 3 used by hard disk BIOS
+#define CBT_F1_DMA3USED (1<<7)
+// 2nd interrupt controller (8259) installed
+#define CBT_F1_2NDPIC   (1<<6)
+// Real-Time Clock installed
+#define CBT_F1_RTC      (1<<5)
+// INT 15/AH=4Fh called upon INT 09h
+#define CBT_F1_INT154F  (1<<4)
+// wait for external event (INT 15/AH=41h) supported
+#define CBT_F1_WAITEXT  (1<<3)
+// extended BIOS area allocated (usually at top of RAM)
+#define CBT_F1_EBDA     (1<<2)
+// bus is Micro Channel instead of ISA
+#define CBT_F1_MCA      (1<<1)
+// system has dual bus (Micro Channel + ISA)
+#define CBT_F1_MCAISA   (1<<0)
+
+// INT 16/AH=09h (keyboard functionality) supported
+#define CBT_F2_INT1609  (1<<6)
+
+struct bios_config_table_s BIOS_CONFIG_TABLE VAR16FIXED(0xe6f5) = {
+    .size     = sizeof(BIOS_CONFIG_TABLE) - 2,
+    .model    = CONFIG_MODEL_ID,
+    .submodel = CONFIG_SUBMODEL_ID,
+    .biosrev  = CONFIG_BIOS_REVISION,
+    .feature1 = (
+        CBT_F1_2NDPIC | CBT_F1_RTC | CBT_F1_EBDA
+        | (CONFIG_KBD_CALL_INT15_4F ? CBT_F1_INT154F : 0)),
+    .feature2 = CBT_F2_INT1609,
+    .feature3 = 0,
+    .feature4 = 0,
+    .feature5 = 0,
+};
+
+
+/****************************************************************
+ * GDT and IDT tables
+ ****************************************************************/
+
+struct descloc_s {
+    u16 length;
+    u32 addr;
+} PACKED;
+
+// Real mode IDT descriptor
+struct descloc_s rmode_IDT_info VAR16_32 = {
+    .length = sizeof(struct rmode_IVT) - 1,
+    .addr = (u32)MAKE_FARPTR(SEG_IVT, 0),
+};
+
+// Dummy IDT that forces a machine shutdown if an irq happens in
+// protected mode.
+u8 dummy_IDT VAR16_32;
+
+// Protected mode IDT descriptor
+struct descloc_s pmode_IDT_info VAR16_32 = {
+    .length = sizeof(dummy_IDT) - 1,
+    .addr = (u32)MAKE_FARPTR(SEG_BIOS, &dummy_IDT),
+};
+
+// GDT
+u64 rombios32_gdt[] VAR16_32 __aligned(8) = {
+    // First entry can't be used.
+    0x0000000000000000LL,
+    // 32 bit flat code segment (SEG32_MODE32_CS)
+    0x00cf9b000000ffffLL,
+    // 32 bit flat data segment (SEG32_MODE32_DS)
+    0x00cf93000000ffffLL,
+    // 16 bit code segment base=0xf0000 limit=0xffff (SEG32_MODE16_CS)
+    0x00009b0f0000ffffLL,
+    // 16 bit data segment base=0x0 limit=0xffff (SEG32_MODE16_DS)
+    0x000093000000ffffLL,
+    // 16 bit code segment base=0 limit=0xffffffff (SEG32_MODE16BIG_CS)
+    0x008f9b000000ffffLL,
+    // 16 bit data segment base=0 limit=0xffffffff (SEG32_MODE16BIG_DS)
+    0x008f93000000ffffLL,
+};
+
+// GDT descriptor
+struct descloc_s rombios32_gdt_48 VAR16_32 = {
+    .length = sizeof(rombios32_gdt) - 1,
+    .addr = (u32)MAKE_FARPTR(SEG_BIOS, rombios32_gdt),
+};
+
+
+/****************************************************************
+ * Misc fixed vars
+ ****************************************************************/
+
+char BiosCopyright[] VAR16FIXED(0xff00) =
+    "(c) 2002 MandrakeSoft S.A. Written by Kevin Lawton & the Bochs team.";
+
+// BIOS build date
+char BiosDate[] VAR16FIXED(0xfff5) = "06/23/99";
+
+u8 BiosModelId VAR16FIXED(0xfffe) = CONFIG_MODEL_ID;
+
+u8 BiosChecksum VAR16FIXED(0xffff);
+
+// XXX - Initial Interrupt Vector Offsets Loaded by POST
+u8 InitVectors[13] VAR16FIXED(0xfef3);
+
+// XXX - INT 1D - SYSTEM DATA - VIDEO PARAMETER TABLES
+u8 VideoParams[88] VAR16FIXED(0xf0a4);