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Diffstat (limited to 'qemu/roms/seabios/src/entryfuncs.S')
| -rw-r--r-- | qemu/roms/seabios/src/entryfuncs.S | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/qemu/roms/seabios/src/entryfuncs.S b/qemu/roms/seabios/src/entryfuncs.S new file mode 100644 index 000000000..7368bb6d5 --- /dev/null +++ b/qemu/roms/seabios/src/entryfuncs.S @@ -0,0 +1,165 @@ +// Macros for entering C code +// +// Copyright (C) 2008-2014 Kevin O'Connor <kevin@koconnor.net> +// +// This file may be distributed under the terms of the GNU LGPLv3 license. + + +/**************************************************************** + * Macros for save and restore of 'struct bregs' registers + ****************************************************************/ + +#define PUSHBREGS_size 32 + + // Save registers (matches struct bregs) to stack + .macro PUSHBREGS + pushl %eax + pushl %ecx + pushl %edx + pushl %ebx + pushl %ebp + pushl %esi + pushl %edi + pushw %es + pushw %ds + .endm + + // Restore registers (from struct bregs) from stack + .macro POPBREGS + popw %ds + popw %es + popl %edi + popl %esi + popl %ebp + popl %ebx + popl %edx + popl %ecx + popl %eax + .endm + + // Save registers to struct bregs at %ds:%eax. The caller + // should "pushw %ds ; pushl %eax" prior to calling - this macro + // will pop them off. + .macro SAVEBREGS_POP_DSEAX + popl BREGS_eax(%eax) + popw BREGS_ds(%eax) + movl %edi, BREGS_edi(%eax) + movl %esi, BREGS_esi(%eax) + movl %ebp, BREGS_ebp(%eax) + movl %ebx, BREGS_ebx(%eax) + movl %edx, BREGS_edx(%eax) + movl %ecx, BREGS_ecx(%eax) + movw %es, BREGS_es(%eax) + .endm + + // Restore registers from struct bregs at %ds:%eax + .macro RESTOREBREGS_DSEAX + movl BREGS_edi(%eax), %edi + movl BREGS_esi(%eax), %esi + movl BREGS_ebp(%eax), %ebp + movl BREGS_ebx(%eax), %ebx + movl BREGS_edx(%eax), %edx + movl BREGS_ecx(%eax), %ecx + movw BREGS_es(%eax), %es + pushl BREGS_eax(%eax) + movw BREGS_ds(%eax), %ds + popl %eax + .endm + + +/**************************************************************** + * Entry macros + ****************************************************************/ + + // Call a C function - this does the minimal work necessary to + // call into C. It sets up %ds, backs up %es, and backs up + // those registers that are call clobbered by the C compiler. + .macro ENTRY cfunc + cli // In case something far-calls instead of using "int" + cld + pushl %eax // Save registers clobbered by C code + pushl %ecx + pushl %edx + pushw %es + pushw %ds + movw %ss, %ax // Move %ss to %ds + movw %ax, %ds + pushl %esp // Backup %esp, then clear high bits + movzwl %sp, %esp + calll \cfunc + popl %esp // Restore %esp (including high bits) + popw %ds // Restore registers saved above + popw %es + popl %edx + popl %ecx + popl %eax + .endm + + // Call a C function with current register list as an + // argument. This backs up the registers and sets %eax + // to point to the backup. On return, the registers are + // restored from the structure. + .macro ENTRY_ARG cfunc + cli + cld + PUSHBREGS + movw %ss, %ax // Move %ss to %ds + movw %ax, %ds + movl %esp, %ebx // Backup %esp, then zero high bits + movzwl %sp, %esp + movl %esp, %eax // First arg is pointer to struct bregs + calll \cfunc + movl %ebx, %esp // Restore %esp (including high bits) + POPBREGS + .endm + + // As above, but get calling function from stack. + .macro ENTRY_ARG_ST + cli + cld + pushl %ecx + pushl %edx + pushl %ebx + pushl %ebp + pushl %esi + pushl %edi + pushw %es + pushw %ds + movw %ss, %cx // Move %ss to %ds + movw %cx, %ds + movl %esp, %ebx // Backup %esp, then zero high bits + movzwl %sp, %esp + movl 28(%esp), %ecx // Get calling function + movl %eax, 28(%esp) // Save %eax + movl %esp, %eax // First arg is pointer to struct bregs + calll *%ecx + movl %ebx, %esp // Restore %esp (including high bits) + POPBREGS + .endm + + // Same as ENTRY_ARG, but don't mangle %esp + .macro ENTRY_ARG_ESP cfunc + cli + cld + PUSHBREGS + movw %ss, %ax // Move %ss to %ds + movw %ax, %ds + movl %esp, %eax // First arg is pointer to struct bregs + calll \cfunc + POPBREGS + .endm + + // Reset stack, transition to 32bit mode, and call a C function. + .macro ENTRY_INTO32 cfunc + xorw %dx, %dx + movw %dx, %ss + movl $ BUILD_STACK_ADDR , %esp + movl $ \cfunc , %edx + jmp transition32 + .endm + + // Declare a function + .macro DECLFUNC func + .section .text.asm.\func + .global \func + .endm |