From 97ac612fb16748e6b011de4deaa803ec5f0afef8 Mon Sep 17 00:00:00 2001 From: rsc Date: Fri, 24 Aug 2007 20:28:08 +0000 Subject: [PATCH] nits --- bootmain.c | 51 ++++++++++++++++++++++++--------------------------- console.c | 34 ++++++++++++++++++---------------- proc.c | 11 +++++------ proc.h | 2 +- syscall.c | 5 +++-- 5 files changed, 51 insertions(+), 52 deletions(-) diff --git a/bootmain.c b/bootmain.c index 6494c16..45b4e53 100644 --- a/bootmain.c +++ b/bootmain.c @@ -31,31 +31,35 @@ #include "x86.h" #define SECTSIZE 512 -#define ELFHDR ((struct elfhdr*) 0x10000) // scratch space void readseg(uint, uint, uint); void cmain(void) { + struct elfhdr *elf; struct proghdr *ph, *eph; + void (*entry)(void); - // read 1st page off disk - readseg((uint) ELFHDR, SECTSIZE*8, 0); + elf = (struct elfhdr*)0x10000; // scratch space - // is this a valid ELF? - if(ELFHDR->magic != ELF_MAGIC) + // Read 1st page off disk + readseg((uint)elf, SECTSIZE*8, 0); + + // Is this an ELF executable? + if(elf->magic != ELF_MAGIC) goto bad; - // load each program segment (ignores ph flags) - ph = (struct proghdr*) ((uchar*) ELFHDR + ELFHDR->phoff); - eph = ph + ELFHDR->phnum; + // Load each program segment (ignores ph flags). + ph = (struct proghdr*)((uchar*)elf + elf->phoff); + eph = ph + elf->phnum; for(; ph < eph; ph++) readseg(ph->va, ph->memsz, ph->offset); - // call the entry point from the ELF header - // note: does not return! - ((void(*)(void)) (ELFHDR->entry & 0xFFFFFF))(); + // Call the entry point from the ELF header. + // Does not return! + entry = (void(*)(void))(elf->entry & 0xFFFFFF); + entry(); bad: outw(0x8A00, 0x8A00); @@ -67,7 +71,7 @@ bad: void waitdisk(void) { - // wait for disk reaady + // Wait for disk ready. while((inb(0x1F7) & 0xC0) != 0x40) ; } @@ -76,9 +80,8 @@ waitdisk(void) void readsect(void *dst, uint offset) { - // wait for disk to be ready + // Issue command. waitdisk(); - outb(0x1F2, 1); // count = 1 outb(0x1F3, offset); outb(0x1F4, offset >> 8); @@ -86,10 +89,8 @@ readsect(void *dst, uint offset) outb(0x1F6, (offset >> 24) | 0xE0); outb(0x1F7, 0x20); // cmd 0x20 - read sectors - // wait for disk to be ready + // Read data. waitdisk(); - - // read a sector insl(0x1F0, dst, SECTSIZE/4); } @@ -98,24 +99,20 @@ readsect(void *dst, uint offset) void readseg(uint va, uint count, uint offset) { - uint end_va; + uint eva; va &= 0xFFFFFF; - end_va = va + count; + eva = va + count; - // round down to sector boundary + // Round down to sector boundary. va &= ~(SECTSIZE - 1); - // translate from bytes to sectors, and kernel starts at sector 1 + // Translate from bytes to sectors; kernel starts at sector 1. offset = (offset / SECTSIZE) + 1; // If this is too slow, we could read lots of sectors at a time. // We'd write more to memory than asked, but it doesn't matter -- // we load in increasing order. - while(va < end_va) { - readsect((uchar*) va, offset); - va += SECTSIZE; - offset++; - } + for(; va < eva; va += SECTSIZE, offset++) + readsect((uchar*)va, offset); } - diff --git a/console.c b/console.c index cc1a0b7..b1518c0 100644 --- a/console.c +++ b/console.c @@ -9,7 +9,11 @@ #include "proc.h" #include "kbd.h" -struct spinlock console_lock; +#define CRTPORT 0x3d4 +#define LPTPORT 0x378 +static ushort *crt = (ushort*)0xb8000; // CGA memory + +static struct spinlock console_lock; int panicked = 0; int use_console_lock = 0; @@ -21,18 +25,16 @@ lpt_putc(int c) { int i; - for(i = 0; !(inb(0x378+1) & 0x80) && i < 12800; i++) + for(i = 0; !(inb(LPTPORT+1) & 0x80) && i < 12800; i++) ; - outb(0x378+0, c); - outb(0x378+2, 0x08|0x04|0x01); - outb(0x378+2, 0x08); + outb(LPTPORT+0, c); + outb(LPTPORT+2, 0x08|0x04|0x01); + outb(LPTPORT+2, 0x08); } static void cons_putc(int c) { - int crtport = 0x3d4; // io port of CGA - ushort *crt = (ushort*) 0xB8000; // base of CGA memory int ind; if(panicked){ @@ -44,10 +46,10 @@ cons_putc(int c) lpt_putc(c); // cursor position, 16 bits, col + 80*row - outb(crtport, 14); - ind = inb(crtport + 1) << 8; - outb(crtport, 15); - ind |= inb(crtport + 1); + outb(CRTPORT, 14); + ind = inb(CRTPORT + 1) << 8; + outb(CRTPORT, 15); + ind |= inb(CRTPORT + 1); c &= 0xff; if(c == '\n'){ @@ -66,17 +68,17 @@ cons_putc(int c) memset(crt + ind, 0, sizeof(crt[0]) * ((24 * 80) - ind)); } - outb(crtport, 14); - outb(crtport + 1, ind >> 8); - outb(crtport, 15); - outb(crtport + 1, ind); + outb(CRTPORT, 14); + outb(CRTPORT + 1, ind >> 8); + outb(CRTPORT, 15); + outb(CRTPORT + 1, ind); } void printint(int xx, int base, int sgn) { + static char digits[] = "0123456789ABCDEF"; char buf[16]; - char digits[] = "0123456789ABCDEF"; int i = 0, neg = 0; uint x; diff --git a/proc.c b/proc.c index 2ed2952..fb79444 100644 --- a/proc.c +++ b/proc.c @@ -65,15 +65,14 @@ growproc(int n) return cp->sz - n; } -// Set up CPU's segment descriptors and task state for a -// given process. -// If p==0, set up for "idle" state for when scheduler() -// is idling, not running any process. +// Set up CPU's segment descriptors and task state for a given process. +// If p==0, set up for "idle" state for when scheduler() is running. void setupsegs(struct proc *p) { - struct cpu *c = &cpus[cpu()]; - + struct cpu *c; + + c = &cpus[cpu()]; c->ts.ss0 = SEG_KDATA << 3; if(p) c->ts.esp0 = (uint)(p->kstack + KSTACKSIZE); diff --git a/proc.h b/proc.h index 137bda3..599ed44 100644 --- a/proc.h +++ b/proc.h @@ -12,7 +12,7 @@ // Save all the regular registers so we don't need to care // which are caller save. // Don't save %eax, because that's the return register. -// The layout of jmpbuf is known to setjmp.S. +// The layout of jmpbuf must match code in setjmp.S. struct jmpbuf { int ebx; int ecx; diff --git a/syscall.c b/syscall.c index 4853e35..d7cf123 100644 --- a/syscall.c +++ b/syscall.c @@ -133,8 +133,9 @@ static int (*syscalls[])(void) = { void syscall(void) { - int num = cp->tf->eax; - + int num; + + num = cp->tf->eax; if(num >= 0 && num < NELEM(syscalls) && syscalls[num]) cp->tf->eax = syscalls[num](); else {