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Commit c5c39856 authored by kexu6's avatar kexu6
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simplify syntax

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student-distrib/syscall.c
+ 0
− 2
View file @ c5c39856
#include "syscall.h"
f_table dir_jumptable = { open_dir, close_dir, read_dir, write_dir };
f_table file_jumptable = { open_file, close_file, read_file, write_file };
f_table rtc_jumptable = { rtc_open, rtc_close, rtc_read, rtc_write };
......@@ -8,7 +7,6 @@ f_table stdin_jumptable = { terminal_open, terminal_close, terminal_read, termi
f_table stdout_jumptable = { terminal_open, terminal_close, terminal_read, terminal_write };
f_table no_jumptable = { fail , fail , fail , fail };
/*
*The halt system call
*
......
student-distrib/syscall.h
+ 1
− 1
View file @ c5c39856
......@@ -52,7 +52,7 @@
#define IF_FLAG 0x200
#define IF_FLAG 0x200
/* Global variables */
//extern int32_t prog_count;
......
student-distrib/syscall_asm.S
+ 32
− 109
View file @ c5c39856
#define ASM 1
#include "x86_desc.h"
#define STACK 0x8400000
#define IF_FLAG 0x200
# Assembly linkage functions
.globl syscall_linkage
.globl context_switch
.globl flush_tlb
#.globl exec_ret
.globl sys_execute_leave
# syscall_linage:
# Description: System call interrupt handler
# Jumps to C function and IRETS to user spaces
# Registers: Saves all (interrupt context)
#syscall_linkage:
#
# # Save flags
# PUSHFL
#
# # Save registers
# pushl %ebx
# pushl %ecx
# pushl %edx
# pushl %esp
# pushl %ebp
# pushl %esi
# pushl %edi
#
#
# # Check for valid system call value
# cmpl $0, %eax
# jbe done
# cmpl $10, %eax
# ja done
#
# # Push arguments on stack
# pushl %edx # 3rd argument
# pushl %ecx # 2nd argument
# pushl %ebx # 1st argument
#
# dec %eax
# # Jump to C function
# call *syscall_jumptable(,%eax,4)
#
# # Pop arguments of stack
# addl $12, %esp
#
#done:
#exec_ret:
# # Restore registers
# popl %edi
# popl %esi
# popl %ebp
# popl %esp
# popl %edx
# popl %ecx
# popl %ebx
#
# # Restore flags
# POPFL
#
## Return to user space
#IRET
syscall_linkage:
# Save flags
pushl $0
PUSHFL
# Save registers
#pushl %eax
# Save registers, do not save eax ???
pushl %ebx
pushl %ecx
pushl %edx
......@@ -98,19 +23,18 @@ syscall_linkage:
pushl %esi
pushl %edi
# Check for valid system call value
# Check for valid system call value (1 through 10)
cmpl $0, %eax
jbe done_invalid
cmpl $10, %eax
ja done_invalid
# Push arguments on stack
pushl %edx # 3rd argument
pushl %ecx # 2nd argument
pushl %ebx # 1st argument
pushl %edx # 3rd argument
pushl %ecx # 2nd argument
pushl %ebx # 1st argument
dec %eax
dec %eax # 1-10 -> 0-9
# Jump to C function
call *syscall_jumptable(,%eax,4)
......@@ -122,8 +46,8 @@ syscall_linkage:
done_invalid:
xorl %eax, %eax
dec %eax
xorl %eax, %eax # set eax to 0
dec %eax # set eax to -1
done:
......@@ -135,7 +59,6 @@ done:
popl %edx
popl %ecx
popl %ebx
#popl %eax
# Restore flags
POPFL
......@@ -154,8 +77,7 @@ sys_execute_leave:
# flush_tlb:
# Description: Reloads CR3
# Required when switching processes
# Registers: Saves callee-saved registers
# Registers: Save callee-saved registers
flush_tlb:
pushl %ebp
......@@ -165,6 +87,7 @@ flush_tlb:
pushl %edi
pushl %esi
# ???
movl %cr3, %eax
movl %eax, %cr3
......@@ -176,38 +99,38 @@ leave
ret
# context_switch:
# Description: Sets up stack for IRET to user program
# Description: Sets up stack for IRET to user program ???
context_switch:
# Load entry point in EBX
movl 4(%esp),%ebx
# Load entry point in EBX
movl 4(%esp),%ebx
# Push SS on stack
xorl %eax, %eax
movw $USER_DS, %ax
pushl %eax
# Push SS on stack
xorl %eax, %eax
movw $USER_DS, %ax
pushl %eax
# Push ESP value for user stack
movl $STACK, %eax
pushl %eax
# Push ESP value for user stack
movl $STACK, %eax
pushl %eax
# Push eflags on stack
pushfl
# Push eflags on stack
pushfl
# Set IF flag in eflags
popl %eax
orl $IF_FLAG,%eax
pushl %eax
# Set IF flag in eflags
popl %eax
orl $IF_FLAG,%eax
pushl %eax
# Push CS on stack
pushl $USER_CS
# Push CS on stack
pushl $USER_CS
# Push EIP for user program
pushl %ebx
# Push EIP for user program
pushl %ebx
# Swicth to user space
iret
IRET
# Jump table for system call C functions
syscall_jumptable:
.long halt, execute, read, write, open, close, getargs, vidmap
.long halt, execute, read, write, open, close, getargs, vidmap
student-distrib/types.h
+ 4
− 11
View file @ c5c39856
......@@ -123,15 +123,13 @@ typedef struct f_table {
/* File Object structure - for PCB */
typedef struct file_object {
f_table fileop_ptr;/* Only valid for data file */
f_table fileop_ptr; /* Only valid for data file */
uint32_t inode_index;
uint32_t file_pos;/* Current position in file, updated by system calls */
uint32_t flags;/* If flag is set, file object is in use */
uint32_t file_pos; /* Current position in file, updated by system calls */
uint32_t flags; /* If flag is set, file object is in use */
} file_object_t;
/* Process control block structure */
typedef struct pcb {
......@@ -157,7 +155,7 @@ typedef struct pcb {
/* Terminal structure - Upto 3 terminals supported */
typedef struct terminal {
pcb_t * pcb;
pcb_t* pcb;
int32_t terminal_x;
int32_t terminal_y;
......@@ -170,9 +168,6 @@ volatile int32_t buffer_index;
} terminal_t;
/*----------------------------- Process Structure ----------------------------*/
typedef struct control {
......@@ -186,7 +181,6 @@ typedef struct control {
} control_t;
/*---------------------------- Global variable -------------------------------*/
/* Godlike--- */
......@@ -194,5 +188,4 @@ control_t control;
#endif /* ASM */
#endif /* _TYPES_H */
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