libseven 0.11.0: split IRQ module for LTO, API rework

- removed CriticalSection functions
- rewrote IRQ API functions in C, for readability/LTO
- renamed IRQ function types, Callback -> Handler
- renamed ISR related macros and types

dist.sh

@@ -11,5 +11,5 @@ make_dist() {
 
 [ ! -d "$DIST" ] && mkdir "$DIST"
 
-(PROJECT=libseven VERSION=0.10.0 make_dist)
+(PROJECT=libseven VERSION=0.11.0 make_dist)
 (PROJECT=minrt VERSION=0.2.0 make_dist)

examples/vsync-callback/src/main.c

@@ -12,7 +12,7 @@ int main(void)
     // Set up the necessary interrupt handling
     irqInitDefault();
     irqEnableFull(IRQ_VBLANK);
-    irqCallbackSet(IRQ_VBLANK, vblank_callback);
+    irqHandlerSet(IRQ_VBLANK, vblank_callback);
 
     // Clear the force-blank bit
     REG_DISPCNT = 0;

libseven/CMakeLists.txt

@@ -13,7 +13,8 @@ add_library(seven STATIC
     src/hw/bios.s
     src/hw/dma.s
     src/hw/input.s
-    src/hw/irq.s
+    src/hw/irq.c
+    src/hw/isr.s
     src/hw/sram.s
     src/hw/timer.s
     src/util/assert.c
@@ -32,7 +33,7 @@ target_include_directories(seven PUBLIC include/)
 target_include_directories(seven PRIVATE src/)
 
 target_compile_options(seven PRIVATE
-    $<$<COMPILE_LANGUAGE:C>:-Os -g3 -gdwarf-4 -ffunction-sections -fdata-sections -ffreestanding -std=c99 -Wall -Wpedantic -mabi=aapcs -mcpu=arm7tdmi -mthumb>
+    $<$<COMPILE_LANGUAGE:C>:-Os -g3 -gdwarf-4 -ffunction-sections -fdata-sections -std=c99 -Wall -Wpedantic -mabi=aapcs -mcpu=arm7tdmi -mthumb>
 )
 
 # Allow the string "libseven" as a parameter for target_link_libraries

libseven/Makefile

@@ -13,7 +13,8 @@ SOURCES = \
 	src/hw/bios.s \
 	src/hw/dma.s \
 	src/hw/input.s \
-	src/hw/irq.s \
+	src/hw/irq.c \
+	src/hw/isr.s \
 	src/hw/sram.s \
 	src/hw/timer.s \
 	src/util/assert.c \
@@ -48,6 +49,7 @@ CFLAGS = \
 BUILD = build
 LIB   = lib
 
+
 #
 # You don't need to touch anything below this point!
 #

libseven/include/seven/hw/irq.h

@@ -11,9 +11,9 @@
 
 _LIBSEVEN_EXTERN_C
 
-// Attribute for compiling functions in a way that is suitable for IRQ handlers.
+// Attribute for compiling functions in a way that is suitable for ISRs.
 //
-#define IRQ_HANDLER     IWRAM_CODE ARM_CODE
+#define ISR_FUNCTION    IWRAM_CODE ARM_CODE
 
 // Interrupt Enable
 //
@@ -27,6 +27,10 @@ _LIBSEVEN_EXTERN_C
 //
 #define REG_IME         VOLADDR(0x04000208, u16)
 
+// Interrupt Service Routine Function Pointer
+//
+#define MEM_ISR         MEMADDR(0x03FFFFFC, IsrFn*)
+
 // IRQ bitflags
 //
 enum IRQ
@@ -83,100 +87,70 @@ enum IRQIndex
 //
 // Function must be ARM code, and ideally be placed in IWRAM.
 //
-// Use the IRQ_HANDLER attribute to mark the function appropriately.
-typedef void IrqHandlerFn(void);
+// Use the ISR_FUNCTION attribute to mark the function appropriately.
+typedef void IsrFn(void);
 
 // Function type for interrupt callbacks.
 //
 // The function receives the triggered IRQs as the first parameter.
-typedef void IrqCallbackFn(u16);
+typedef void IrqHandlerFn(u16);
 
 // Initialize interrupt handling with a user-provided function.
 //
-extern void irqInit(IrqHandlerFn *isr);
+extern void irqInit(IsrFn *isr);
 
-// Initialize interrupt handling using a callback system.
+// Initialize interrupt handling using a handler system.
 //
+// Used with the irqHandler* functions.
 extern void irqInitDefault(void);
 
-// Initialize interrupt handling using a single callback function.
-//
-// irqInitSimple(my_callback) is roughly similar to
-// irqCallbackSet(IRQS_ALL, my_callback, 0),
-// but has a lower overhead.
+// Initialize interrupt handling using a single handler function.
 //
-extern void irqInitSimple(IrqCallbackFn *fn);
+extern void irqInitSimple(IrqHandlerFn *fn);
 
 // Initialize interrupt handling using a stub handler
 // that only acknowledges the IRQs and returns.
 //
-// This is enough for svcHalt, svcIntrWait, and svcVBlankIntrWait to work.
-//
+// This is enough for the BIOS interrupt wait functions to work.
 extern void irqInitStub(void);
 
-// Set the callback associated with the specified irq.
+// Set the handler associated with the specified irq.
 //
 // Fails if irq specifies more than one interrupt.
-//
-extern bool irqCallbackSet(u16 irq, IrqCallbackFn *fn);
+extern bool irqHandlerSet(u16 irq, IrqHandlerFn *fn);
 
 // Get the callback associated with the specified irq.
 //
-// Returns null if irq specifies more than one interrupt, or no callback is set.
-extern IrqCallbackFn* irqCallbackGet(u16 irq);
+// Fails if irq specifies more than one interrupt.
+extern bool irqHandlerGet(u16 irq, IrqHandlerFn **fn);
+
+// Swap the handler associated with the specified irq, returning the old one.
+//
+// Fails if irq specifies more than one interrupt.
+extern bool irqHandlerSwap(u16, IrqHandlerFn **fn);
 
 // Enable the specified IRQs.
 //
 // Returns the old value of the IE register.
-//
 extern u16 irqEnable(u16 irqs);
 
 // Disable the specified IRQs.
 //
 // Returns the old value of the IE register.
-//
 extern u16 irqDisable(u16 irqs);
 
-// Enable the specified IRQs and set the matching I/O registers.
+// Enable the specified IRQs and IRQ enable bits in the respective IO registers.
 //
 // Returns the old value of the IE register.
-//
 extern u16 irqEnableFull(u16 irqs);
 
-// Disable the specified IRQs and set the matching I/O registers.
+// Disable the specified IRQs and IRQ enable bits in the respective IO registers.
 //
 // Returns the old value of the IE register.
-//
 extern u16 irqDisableFull(u16 irqs);
 
-// Saves the current value of the IME register and disables it until
-// a call to irqCriticalSectionExit.
-//
-// Calls can be nested. Only the outermost call affects IME.
-//
-extern void irqCriticalSectionEnter(void);
-
-// Restores the value of IME saved by a
-// previous call to irqCriticalSectionEnter.
-//
-// Only the outermost call affects IME.
-//
-extern void irqCriticalSectionExit(void);
-
-// Returns true if currently inside a critical section.
-//
-extern bool irqCriticalSectionActive(void);
-
-// Calls the function f with IRQs disabled, passing data as an argument.
-//
-// Equivalent to
-//
-// bool i = REG_IME;
-// REG_IME = 0;
-// f(data);
-// REG_IME = i;
-// return;
-extern void irqFree(void (*f)(void*), void *data);
+// Calls a function with IRQs disabled, passing data as an argument.
+extern void irqFree(void (*f)(void*), void *arg);
 
 _LIBSEVEN_EXTERN_C_END
 

libseven/meson.build

@@ -1,10 +1,11 @@
-version = '0.10.0'
+version = '0.11.0'
 
 sources = [
   'src/hw/bios.s',
   'src/hw/dma.s',
   'src/hw/input.s',
-  'src/hw/irq.s',
+  'src/hw/irq.c',
+  'src/hw/isr.s',
   'src/hw/sram.s',
   'src/hw/timer.s',
   'src/util/assert.c',

libseven/src/hw/irq.c

@@ -0,0 +1,131 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <seven/base.h>
+#include <seven/hw/irq.h>
+
+extern IsrFn isrDefault;
+extern IsrFn isrSimple;
+extern IsrFn isrStub;
+
+extern IrqHandlerFn* ISR_SIMPLE_HANDLER;
+extern IrqHandlerFn* ISR_DEFAULT_HANDLERS[16];
+
+extern void irqInit(IsrFn *isr)
+{
+    REG_IME = 0;
+    REG_IE = 0;
+    REG_IF = 0xFFFF;
+
+    MEM_ISR = isr;
+
+    REG_IME = 1;
+    return;
+}
+
+extern void irqInitDefault(void)
+{
+    REG_IME = 0;
+
+    for (usize i = 0; i < 16; i++)
+    {
+        ISR_DEFAULT_HANDLERS[i] = NULL;
+    }
+
+    irqInit(isrDefault);
+}
+
+extern void irqInitSimple(IrqHandlerFn *handler)
+{
+    REG_IME = 0;
+
+    ISR_SIMPLE_HANDLER = handler;
+
+    irqInit(isrSimple);
+}
+
+extern void irqInitStub(void)
+{
+    irqInit(isrStub);
+}
+
+extern bool irqHandlerSet(u16 irq, IrqHandlerFn *fn)
+{
+    if (!irq || (irq & (irq - 1)))
+    {
+        return false;
+    }
+
+    ISR_DEFAULT_HANDLERS[(0x09AF0000 * irq) >> 28] = fn;
+
+    return true;
+}
+
+extern bool irqHandlerGet(u16 irq, IrqHandlerFn **fn)
+{
+    if (!irq || (irq & (irq - 1)))
+    {
+        return false;
+    }
+
+    *fn = ISR_DEFAULT_HANDLERS[(0x09AF0000 * irq) >> 28];
+
+    return true;
+}
+
+extern bool irqHandlerSwap(u16 irq, IrqHandlerFn **fn)
+{
+    if (!irq || (irq & (irq - 1)))
+    {
+        return false;
+    }
+
+    u32 idx = (0x09AF0000 * irq) >> 28;
+
+    IrqHandlerFn *p = ISR_DEFAULT_HANDLERS[idx];
+    ISR_DEFAULT_HANDLERS[idx] = *fn;
+    *fn = p;
+
+    return true;
+}
+
+extern u16 irqEnable(u16 irqs)
+{
+    u32 ime = REG_IME;
+    REG_IME = 0;
+
+    u16 old = REG_IE;
+    REG_IE = old | irqs;
+
+    REG_IME = ime;
+
+    return old;
+}
+
+extern u16 irqDisable(u16 irqs)
+{
+    u32 ime = REG_IME;
+    REG_IME = 0;
+
+    u16 old = REG_IE;
+    REG_IE = old & ~irqs;
+
+    REG_IME = ime;
+
+    return old;
+}
+
+extern void irqFree(void (*f)(void*), void *arg)
+{
+    u32 ime = REG_IME;
+    REG_IME = 0;
+
+    f(arg);
+
+    REG_IME = ime;
+
+    return;
+}