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Filename : CRT0FPU.S

/* copro struct */

#define i_orgeip _info
#define i_retsys _info+4
#define i_ebx _info+8
#define i_ecx _info+12
#define i_edx _info+16
#define i_esi _info+20
#define i_edi _info+24
#define i_ebp _info+28
#define i_eax _info+32
#define i_ds _info+36
#define i_es _info+40
#define i_fs _info+44
#define i_gs _info+48
#define i_orgeax _info+52
#define i_eip _info+56
#define i_cs _info+60
#define i_eflags _info+64
#define i_esp _info+68
#define i_ss _info+72

#define i_vm86_es _info+76
#define i_vm86_ds _info+80
#define i_vm86_fs _info+84
#define i_vm86_gs _info+88


.globl _fpu_entry
.globl _back_to_prg
.globl _debugged
.globl _used_math
.globl _raise

.text

/* called from extender: 1. init exception ; 2. change mathe state */
/* gs = emu data seg */

_fpu_entry:
cmpl $0x12345678,%eax /* init call ? */
jz L10
movl %edx, %gs:_debugged /* debugged>0 : don't lookahead */
movl %ecx, %gs:_used_math /* used_math>0: don't init */
lret


/* ! can't use movl %eax,gs:xx (bug ??) */


_emu_selector:
.long 0

.align 2,144
/* init exception vector 7 */
L10:
movw %gs, %cx
movw %cx, %gs:_emu_selector /* save dataseg in code */
movw %edx, %gs:emu_esp /* save dataseg in code */

movw %cs,%cx /* cx:edx exception-handler */
movl $_exception7,%edx
movw $0x203,%ax
movw $0x7,%bx /* 387 exception */
int $0x31
jnc 1f
movl $0,%eax /* 0 = error */
jmp 2f
1:
movl $_copro , %eax /* return coprostruct */
2:
lret



/* stack after exception :
*
* 0 = DPMIeip,
* 4 = DPMIcs,
* 8 = error code,
* 12 = eip,
* 16 = cs,
* 20 = eflags,
* 24 = esp,
* 28 = ss
*/

#define EIP 12
#define CS 16
#define EFLAGS 20
#define ESP 24
#define SS 28

/* entry for emulation :
** ds,es,fs,gs = user_prg_ds
** stack = dpmi-server ss,esp
*/

.align 2,144
_exception7:
pushl %cs:_emu_selector /* load datasegment */
popl %ds

movw %es, i_ds
movw %es, i_es
movw %fs, i_fs
movl %eax, i_eax
movl %eax, i_orgeax
movl %ebx, i_ebx
movl %ecx, i_ecx
movl %edx, i_edx
movl %esi, i_esi
movl %edi, i_edi
movl %ebp, i_ebp


/* save regs on dpmi stack */
movl EIP(%esp), %eax
movl %eax, i_orgeip
movl %eax, i_eip
movl CS(%esp), %eax
movl %eax, i_cs
movl EFLAGS(%esp), %eax
andl $0xFFFEFFFF,%eax /* clear resume flag */
movl %eax, i_eflags
andl $0xFFFFFEFF,%eax /* clear step flag */
orl $0x200,%eax /* set iflag */
movl %eax, EFLAGS(%esp) /* save back */
movl ESP(%esp), %eax
movl %eax, i_esp
movl SS(%esp), %eax
movl %eax, i_ss

/* prepare stack frame for lret */
movw %ds, %ax
movw %ax, SS(%esp)
movl emu_esp, %eax
movl %eax, ESP(%esp)
movw %cs, %ax
movw %ax, CS(%esp)
movl $emulate, %eax
movl %eax, EIP(%esp)

/* resore eax (not necessary?) */
movl i_eax, %eax
pushl %es
popl %ds

lret
/* back to dpmi-handler */
/* jmp to our handler cs:emulate */


/* called from DPMI-server after return from exception7 */
/* cs:eip and ss:esp are ok */

.align 2,144
emulate:
movw %ss, %ax /* set ds,es */
movw %ax, %ds
movw %ax, %es
pushl $_info
call _math_emulate
_back_to_prg:
movl i_eax,%eax
movl i_ebx,%ebx
movl i_ecx,%ecx
movl i_edx,%edx
movl i_esi,%esi
movl i_edi,%edi
movl i_ebp,%ebp
movw i_es,%es
movw i_fs,%fs

movw i_ss,%ss /* change stack to user */
movl i_esp,%esp

pushl i_eflags
pushl i_cs
pushl i_eip
movw i_ds,%ds
iret

_abort_emu:
_raise:
movw $0x7f0e,%ax
movw $0x8 ,%cx
int $0x21

movw $0x4cff,%ax
int $0x21
ret



.data

rsxfpu_ver:
.long 109

dpmi_esp:
.long 0
dpmi_ss:
.long 0
emu_esp:
.long 0xfff0
_debugged:
.long 0
_used_math:
.long 0

.globl _process_npx
_process_npx:
.long _copro

.lcomm _copro,172
.comm _info,92