Re: [Qemu-devel] [PATCH] Save 3MB ioport table memory

[Samuel Thibault <samuel.thibault@eu.citrix.com>]

Paul Brook, le Wed 23 Jul 2008 13:15:42 +0100, a écrit :
> Why are you leaving empty functions?

In case somebody wants to fill it again? :)

> > +static uint32_t default_ioport_readi(int index, uint32_t address)
> 
> While the abstraction is good, I don't like the name of this function.
> I'd expect this to be a direct wrapper round default_ioport_read[bwl], not 
> something that calls the actual IO port handler.

Ah, right, here is an updated patch.

Samuel



Save 1.5MB (32bit) or 3MB (64bit) memory by keeping ioport tables
sparse and use a test against NULL instead.

Signed-off-by: Samuel Thibault <samuel.thibault@eu.citrix.com>

Index: vl.c
===================================================================
--- vl.c	(révision 4924)
+++ vl.c	(copie de travail)
@@ -260,6 +260,35 @@
 target_phys_addr_t isa_mem_base = 0;
 PicState2 *isa_pic;
 
+static IOPortReadFunc default_ioport_readb, default_ioport_readw, default_ioport_readl;
+static IOPortWriteFunc default_ioport_writeb, default_ioport_writew, default_ioport_writel;
+
+static uint32_t ioport_read(int index, uint32_t address)
+{
+    static IOPortReadFunc *default_func[3] = {
+        default_ioport_readb,
+        default_ioport_readw,
+        default_ioport_readl
+    };
+    IOPortReadFunc *func = ioport_read_table[index][address];
+    if (!func)
+        func = default_func[index];
+    return func(ioport_opaque[address], address);
+}
+
+static void ioport_write(int index, uint32_t address, uint32_t data)
+{
+    static IOPortWriteFunc *default_func[3] = {
+        default_ioport_writeb,
+        default_ioport_writew,
+        default_ioport_writel
+    };
+    IOPortWriteFunc *func = ioport_write_table[index][address];
+    if (!func)
+        func = default_func[index];
+    func(ioport_opaque[address], address, data);
+}
+
 static uint32_t default_ioport_readb(void *opaque, uint32_t address)
 {
 #ifdef DEBUG_UNUSED_IOPORT
@@ -279,17 +308,17 @@
 static uint32_t default_ioport_readw(void *opaque, uint32_t address)
 {
     uint32_t data;
-    data = ioport_read_table[0][address](ioport_opaque[address], address);
+    data = ioport_read(0, address);
     address = (address + 1) & (MAX_IOPORTS - 1);
-    data |= ioport_read_table[0][address](ioport_opaque[address], address) << 8;
+    data |= ioport_read(0, address) << 8;
     return data;
 }
 
 static void default_ioport_writew(void *opaque, uint32_t address, uint32_t data)
 {
-    ioport_write_table[0][address](ioport_opaque[address], address, data & 0xff);
+    ioport_write(0, address, data & 0xff);
     address = (address + 1) & (MAX_IOPORTS - 1);
-    ioport_write_table[0][address](ioport_opaque[address], address, (data >> 8) & 0xff);
+    ioport_write(0, address, (data >> 8) & 0xff);
 }
 
 static uint32_t default_ioport_readl(void *opaque, uint32_t address)
@@ -307,20 +336,6 @@
 #endif
 }
 
-static void init_ioports(void)
-{
-    int i;
-
-    for(i = 0; i < MAX_IOPORTS; i++) {
-        ioport_read_table[0][i] = default_ioport_readb;
-        ioport_write_table[0][i] = default_ioport_writeb;
-        ioport_read_table[1][i] = default_ioport_readw;
-        ioport_write_table[1][i] = default_ioport_writew;
-        ioport_read_table[2][i] = default_ioport_readl;
-        ioport_write_table[2][i] = default_ioport_writel;
-    }
-}
-
 /* size is the word size in byte */
 int register_ioport_read(int start, int length, int size,
                          IOPortReadFunc *func, void *opaque)
@@ -394,7 +409,7 @@
     if (loglevel & CPU_LOG_IOPORT)
         fprintf(logfile, "outb: %04x %02x\n", addr, val);
 #endif
-    ioport_write_table[0][addr](ioport_opaque[addr], addr, val);
+    ioport_write(0, addr, val);
 #ifdef USE_KQEMU
     if (env)
         env->last_io_time = cpu_get_time_fast();
@@ -407,7 +422,7 @@
     if (loglevel & CPU_LOG_IOPORT)
         fprintf(logfile, "outw: %04x %04x\n", addr, val);
 #endif
-    ioport_write_table[1][addr](ioport_opaque[addr], addr, val);
+    ioport_write(1, addr, val);
 #ifdef USE_KQEMU
     if (env)
         env->last_io_time = cpu_get_time_fast();
@@ -420,7 +435,7 @@
     if (loglevel & CPU_LOG_IOPORT)
         fprintf(logfile, "outl: %04x %08x\n", addr, val);
 #endif
-    ioport_write_table[2][addr](ioport_opaque[addr], addr, val);
+    ioport_write(2, addr, val);
 #ifdef USE_KQEMU
     if (env)
         env->last_io_time = cpu_get_time_fast();
@@ -430,7 +445,7 @@
 int cpu_inb(CPUState *env, int addr)
 {
     int val;
-    val = ioport_read_table[0][addr](ioport_opaque[addr], addr);
+    val = ioport_read(0, addr);
 #ifdef DEBUG_IOPORT
     if (loglevel & CPU_LOG_IOPORT)
         fprintf(logfile, "inb : %04x %02x\n", addr, val);
@@ -445,7 +460,7 @@
 int cpu_inw(CPUState *env, int addr)
 {
     int val;
-    val = ioport_read_table[1][addr](ioport_opaque[addr], addr);
+    val = ioport_read(1, addr);
 #ifdef DEBUG_IOPORT
     if (loglevel & CPU_LOG_IOPORT)
         fprintf(logfile, "inw : %04x %04x\n", addr, val);
@@ -460,7 +475,7 @@
 int cpu_inl(CPUState *env, int addr)
 {
     int val;
-    val = ioport_read_table[2][addr](ioport_opaque[addr], addr);
+    val = ioport_read(2, addr);
 #ifdef DEBUG_IOPORT
     if (loglevel & CPU_LOG_IOPORT)
         fprintf(logfile, "inl : %04x %08x\n", addr, val);
@@ -8832,8 +8847,6 @@
     register_savevm("timer", 0, 2, timer_save, timer_load, NULL);
     register_savevm("ram", 0, 2, ram_save, ram_load, NULL);
 
-    init_ioports();
-
     /* terminal init */
     memset(&display_state, 0, sizeof(display_state));
     if (nographic) {