Replace __call16 hardcoded offsets with auto generated struct offsets.
Also, load/save %ds register in __call16().
@echo " Precompiling $<"
$(Q)$(CPP) -P -D__ASSEMBLY__ $< -o $@
+$(OUT)asm-offsets.h: $(OUT)asm-offsets.16.s
+ @echo " Generating offset file $@"
+ $(Q)./tools/gen-offsets.sh $< $@
$(OUT)blob.16.s: ; $(call whole-compile, $(CFLAGS16) -S, $(addprefix src/, $(SRC16)),$@)
TABLEASM=$(addprefix $(OUT), $(patsubst %.c,%.proc.16.s,$(TABLESRC)))
-$(OUT)romlayout16.o: romlayout.S $(OUT)blob.16.s $(TABLEASM)
+$(OUT)romlayout16.o: romlayout.S $(OUT)blob.16.s $(OUT)asm-offsets.h $(TABLEASM)
@echo " Generating 16bit layout of $@"
$(Q)$(CC) $(CFLAGS16) -c -D__ASSEMBLY__ $< -o $@
--- /dev/null
+// Generate assembler offsets.
+
+#include "gen-defs.h"
+#include "bregs.h"
+
+/* workaround for a warning with -Wmissing-prototypes */
+void foo(void) VISIBLE16;
+
+void foo(void)
+{
+ OFFSET(BREGS_es, bregs, es);
+ OFFSET(BREGS_ds, bregs, ds);
+ OFFSET(BREGS_eax, bregs, eax);
+ OFFSET(BREGS_ebx, bregs, ebx);
+ OFFSET(BREGS_ecx, bregs, ecx);
+ OFFSET(BREGS_edx, bregs, edx);
+ OFFSET(BREGS_esi, bregs, esi);
+ OFFSET(BREGS_edi, bregs, edi);
+ OFFSET(BREGS_flags, bregs, flags);
+ OFFSET(BREGS_ip, bregs, ip);
+}
--- /dev/null
+// Tool for building defintions accessible from assembler code. This
+// is based on code from the Linux Kernel.
+#ifndef __GEN_DEFS_H
+#define __GEN_DEFS_H
+
+
+#define DEFINE(sym, val) \
+ asm volatile("\n->" #sym " %0 " #val : : "i" (val))
+
+#define BLANK() \
+ asm volatile("\n->" : : )
+
+#define OFFSET(sym, str, mem) \
+ DEFINE(sym, offsetof(struct str, mem))
+
+#define COMMENT(x) \
+ asm volatile("\n->#" x)
+
+#endif // gen-defs.h
#include "config.h" // CONFIG_*
#include "ioport.h" // PORT_A20
#include "bregs.h" // CR0_*
+#include "../out/asm-offsets.h" // BREGS_*
/****************************************************************
// Setup for iretw call
pushw $SEG_BIOS
pushw $1f // return point
- pushw 0x20(%eax) // flags
- pushl 0x1c(%eax) // CS:IP
+ pushw BREGS_flags(%eax) // flags
+ pushl BREGS_ip(%eax) // CS:IP
// Load calling registers.
- movl 0x04(%eax), %edi
- movl 0x08(%eax), %esi
- movl 0x0c(%eax), %ebx
- movl 0x10(%eax), %edx
- movl 0x14(%eax), %ecx
- movw 0x02(%eax), %es // XXX - should load %ds too
- movl 0x18(%eax), %eax
+ movl BREGS_edi(%eax), %edi
+ movl BREGS_esi(%eax), %esi
+ movl BREGS_ebx(%eax), %ebx
+ movl BREGS_edx(%eax), %edx
+ movl BREGS_ecx(%eax), %ecx
+ movw BREGS_es(%eax), %es
+ movw BREGS_ds(%eax), %ds
+ movl %ss:BREGS_eax(%eax), %eax
// Invoke call
iretw // XXX - just do a lcalll
pushfw
pushl %eax
movl 0x06(%esp), %eax
- movl %ecx, %ss:0x14(%eax) // Save %ecx
+ movl %ecx, %ss:BREGS_ecx(%eax)
+ movw %ds, %ss:BREGS_ds(%eax)
movw %ss, %cx
- movw %cx, %ds // Restore %ds == %ss
+ movw %cx, %ds // Restore %ds == %ss
popl %ecx
- movl %ecx, 0x18(%eax) // Save %eax
+ movl %ecx, BREGS_eax(%eax)
popw %cx
- movw %cx, 0x20(%eax) // Save flags
+ movw %cx, BREGS_flags(%eax)
// Store remaining registers
- movw %es, 0x02(%eax)
- movl %edi, 0x04(%eax)
- movl %esi, 0x08(%eax)
- movl %ebx, 0x0c(%eax)
- movl %edx, 0x10(%eax)
+ movw %es, BREGS_es(%eax)
+ movl %edi, BREGS_edi(%eax)
+ movl %esi, BREGS_esi(%eax)
+ movl %ebx, BREGS_ebx(%eax)
+ movl %edx, BREGS_edx(%eax)
// Remove %eax
popl %eax
--- /dev/null
+:
+# Extract definitions from an assembler file. This is based on code
+# from the Linux Kernel.
+INFILE=$1
+OUTFILE=$2
+cat > "$OUTFILE" <<EOF
+// This is an auto-generated file. DO NOT EDIT!
+// Generated with "$0 $@"
+#ifndef __ASM_OFFSETS_H
+#define __ASM_OFFSETS_H
+EOF
+sed -ne "/^->/{s:->#\(.*\):/* \1 */:; \
+ s:^->\([^ ]*\) [\$\#]*\([^ ]*\) \(.*\):#define \1 \2 /* \3 */:; \
+ s:->::; p;}" < "$INFILE" >> "$OUTFILE"
+cat >> "$OUTFILE" <<EOF
+#endif // asm-offsets.h
+EOF