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/* Copyright (C) 1994, 1995 Charles Sandmann (sandmann@clio.rice.edu)
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* This file maybe freely distributed and modified as long as copyright remains.
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/* Length 64 bytes plus non-used FPU */
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.comm exception_stack, 8000
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.macro EXCEPTION_ENTRY number
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.global ___djgpp_exception_table
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___djgpp_exception_table:
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/* This code is called any time an exception occurs in the 32 bit protected
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;* mode code. The exception number is pushed on the stack. This is called
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;* on a locked stack with interrupts disabled. Don't try to terminate.
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;* [ * | SS ] * Don't modify
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;* [ * | CS ] * Don't modify
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;* [ * |RET CS*] * Don't modify
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;* [ RET EIP* ] * Don't modify
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;* [ EXCEPTION # ] (And later EBP)
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/* ;WARNING WARNING WARNING
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;The mechanism for passing signals between the debugger
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;and the debuggee relies on the *exact* instructions between
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;EXCEPTION_ENTRY($13) above and "cmpb $0, forced" instruction
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;below! These instructions are stored in forced_test[] buffer
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;in src/debug/common/dbgcom.c. Do NOT change anything between
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;these two instructions, or you will break signal support in
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movl %ebx,8(%esp) /* replace EXCEPNO */
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movzwl ___djgpp_fpu_state,%ebx
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movl %ebx,20(%esp) /* set ERRCODE to FPU state */
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movw %cs:___djgpp_our_DS, %ds
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movl $0x10000, forced /* its zero now, flag inuse */
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movl $exception_state, %ebx
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movl ___djgpp_exception_state_ptr, %eax
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movl %eax, PREVEXC(%ebx)
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/* Stack clean at this point, DS:[EBX] points to exception_state, all
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register information saved. Now get the info on stack. */
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movl %esp, %ebp /* load ebp with stack for easy access */
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movl %eax, ERRCODE(%ebx)
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movl %eax, EFLAGS(%ebx)
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andb $0xfe, %ah /* Clear trace flag */
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movl %eax, 24(%ebp) /* and restore on stack */
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movl $dpmi_exception_proc1, 16(%ebp) /* where to return */
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/* Change to our local stack on return from exception (maybe stack exception) */
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cmpb $12,EXCEPNO(%ebx) /* Stack fault ? */
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movw ___djgpp_ds_alias,%di
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cmpw %di,32(%ebp) /* if it's DS alias, switch to normal DS */
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1: movl $exception_stack+8000, 28(%ebp)
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/* Now copy the exception structure to the new stack before returning */
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subl $92, %edi /* 64 plus extra for longjmp */
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movl %edi, ___djgpp_exception_state_ptr
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movl EAX(%ebx), %eax /* restore regs */
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movb $0, forced+2 /* flag non-use */
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/* Code to fix fake exception, EBX destroyed. Note, app_DS may == our_DS! */
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movl ___djgpp_app_DS, %ebx /* avoid size prefix */
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int $0x31 /* Set segment limit */
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/* This local routine preprocesses a return request to the C code. It checks
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to make sure the DS & SS are set OK for C code. If not, it sets them up */
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dpmi_exception_proc1:
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.byte 0x2e /* CS: !!! */
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movw ___djgpp_our_DS, %bx /* to be sure */
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/* Note: SS:ESP should be set properly by exception routine */
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jmp ___djgpp_exception_processor
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/* This code is called by a user routine wishing to save an interrupt
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;* state. It will return with a clean stack, our DS,ES,SS.
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;* Minor bug: uses static exception_state for a short window without
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;* interrupts guaranteed disabled.
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.globl ___djgpp_save_interrupt_regs
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___djgpp_save_interrupt_regs:
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movw %cs:___djgpp_our_DS, %ds
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movl $exception_state, %esi
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popl DS(%esi) /* Trashes ES but OK */
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popl %edx /* Save calling EIP */
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movw %ax,CS(%esi) /* Don't pop, nukes DS */
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movl ___djgpp_exception_state_ptr, %eax
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movl %eax, PREVEXC(%esi)
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cmpw %ax, %bx /* is SS = DS ? */
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movw %ax, %ss /* set new SS:ESP */
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movl $exception_stack+8000, %esp
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Lss_ok: subl $92, %esp /* 64 plus extra for longjmp */
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movl %edi, ___djgpp_exception_state_ptr
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movsl /* Copy structure to stack */
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jmp *%edx /* A "return" */
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.balign 8 /* We will touch this; it must be locked */
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.global ___djgpp_hw_lock_start
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___djgpp_hw_lock_start:
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/* src/debug/common/dbgcom.c knows that `ds_limit' is stored
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4 bytes before `forced' and relies on that. Do NOT change that! */
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.global ___djgpp_cbrk_count
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___djgpp_cbrk_count: .long 0
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.global ___djgpp_timer_countdown
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___djgpp_timer_countdown: .long 0
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.global ___djgpp_our_DS
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___djgpp_our_DS: .word 0
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.global ___djgpp_app_DS
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___djgpp_app_DS: .word 0
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.global ___djgpp_dos_sel
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___djgpp_dos_sel: .word 0
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.global ___djgpp_hwint_flags
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___djgpp_hwint_flags: .word 0
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.global ___djgpp_sigint_key
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___djgpp_sigint_key: .word 0 /* scan code and kb status */
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.global ___djgpp_sigint_mask
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___djgpp_sigint_mask: .word 0 /* kb status mask */
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.global ___djgpp_sigquit_key
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___djgpp_sigquit_key: .word 0
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.global ___djgpp_sigquit_mask
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___djgpp_sigquit_mask: .word 0
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.global ___djgpp_old_kbd
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___djgpp_old_kbd: .long 0,0
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.global ___djgpp_old_timer
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___djgpp_old_timer: .long 0,0
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.global ___djgpp_exception_state_ptr
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___djgpp_exception_state_ptr: .long 0
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exception_state: .space 64
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.global ___djgpp_ds_alias
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___djgpp_ds_alias: .word 0 /* used in dpmi/api/d0303.s (alloc rmcb) */
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.global ___djgpp_fpu_state
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___djgpp_fpu_state: .word 0
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.global ___djgpp_npx_hdlr
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fnstsw ___djgpp_fpu_state
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call ___djgpp_hw_exception
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.global ___djgpp_kbd_hdlr
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testb $1, ___djgpp_hwint_flags /* Disable? */
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movw %cs:___djgpp_dos_sel, %ds /* Conventional mem selector */
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/* movw $0x7021,0xb0f00 */ /* Test code - write to mono */
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/* Check Keyboard status bits */
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movb 0x417,%ah /* Get KB status byte */
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orb $2,%ah /* If RShift is set, set LShift as well */
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inb $0x60,%al /* Read the scan code */
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movb %ah,%bh /* Save KB status */
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andb %cs:___djgpp_sigint_mask, %ah /* Mask off irrelevant bits */
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cmpw %cs:___djgpp_sigint_key, %ax /* Test for SIGINT */
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movb $0x79,%bh /* SIGINT */
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movb %bh,%ah /* Restore KB status */
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andb %cs:___djgpp_sigquit_mask, %ah /* Mask off irrelevant bits */
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cmpw %cs:___djgpp_sigquit_key, %ax /* Test for SIGQUIT*/
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movb $0x7a,%bh /* SIGQUIT */
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/* Clear interrupt, (later: remove byte from controller?)
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call ___djgpp_hw_exception
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ljmp %cs:___djgpp_old_kbd
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.global ___djgpp_kbd_hdlr_pc98
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___djgpp_kbd_hdlr_pc98:
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testb $1, ___djgpp_hwint_flags /* Disable? */
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/* Check CTRL state */
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movw %cs:___djgpp_dos_sel, %ds /* Conventional mem selector */
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movb 0x053a,%al /* Get KB status byte */
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/* Convert PC98 style status byte to PC/AT style */
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andb $0x09,%ah /* GRPH(=ALT), SHIFT(=R-Shift) */
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orb $0x40,%ah /* CAPS(=Caps Lock) */
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orb $0x04,%ah /* CTRL(=Ctrl) */
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orb $0x02,%ah /* SHIFT(=L-Shift) */
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orb $0x20,%ah /* KANA(=NUM Lock) */
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984: inb $0x41,%al /* Read the scan code */
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.global ___djgpp_timer_hdlr
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cmpl $0,___djgpp_timer_countdown
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movw %cs:___djgpp_ds_alias, %ds
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decl ___djgpp_timer_countdown
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call ___djgpp_hw_exception
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testb $4, ___djgpp_hwint_flags /* IRET or chain? */
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ljmp %cs:___djgpp_old_timer
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movb $0x20,%al /* EOI the interrupt */
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/* On entry ES is the DS alias selector */
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.global ___djgpp_cbrk_hdlr /* A RMCB handler for 0x1b */
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lodsl /* EAX = DS:[esi] CS:IP */
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movl %eax, %es:0x2a(%edi) /* store in structure */
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lodsl /* AX = FLAGS */
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movw %ax, %es:0x20(%edi)
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addw $6, %es:0x2e(%edi) /* Adjust RM SP */
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testb $2, ___djgpp_hwint_flags /* Count, don't kill */
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call ___djgpp_hw_exception
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incl %es:___djgpp_cbrk_count
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.global ___djgpp_i24 /* Int 24 handler if needed */
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.global ___djgpp_iret /* Int 23 handler if needed */
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/* Code to stop execution ASAP, EAX destroyed. Make DS/ES/SS invalid.
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Fake exception value is passed in AL and moved into the "forced" variable.
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This is used to convert a HW interrupt into something we can transfer
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control away from via longjmp or exit(), common with SIGINT, SIGFPE, or
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if we want EIP information on timers. */
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.global ___djgpp_hw_exception
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___djgpp_hw_exception:
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cmpl $0, forced /* Already flagged? */
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movw %cs:___djgpp_our_DS, %ds
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movl ___djgpp_app_DS, %ebx /* avoid size prefix */
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movl %ecx, ds_limit /* Save current limit */
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movb %al, forced /* Indicate a fake exception */
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movw $0xfff, %dx /* 4K limit is null page ! */
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int $0x31 /* Set segment limit */
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.global ___djgpp_hw_lock_end
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___djgpp_hw_lock_end:
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ret /* LD does weird things */
added
removed
rtl/go32v2/exceptn.as
