[Fixes]: Fix ISR premption

Udhayanandhan-Jayakumar · MuhammedZamroodh · commit a4f16dd32cfb · 2025-11-25T09:28:15.000+05:30
[Description]:
        Fixed use of neop instruction (used nop instead)
        Doc fixes in arch and board
        Added optimisation levels
        ISR vector number lost on premption, fixed by adding
        workaround for for alternate vec number calculation

Signed-off-by: Muhammed Zamroodh &lt;muhammed.zamroodh@ignitarium.com&gt;
diff --git a/arch/Kconfig b/arch/Kconfig
@@ -579,6 +579,7 @@ choice IRQ_VECTOR_TABLE_TYPE
 	prompt "IRQ vector table type"
 	depends on GEN_IRQ_VECTOR_TABLE
 	default IRQ_VECTOR_TABLE_JUMP_BY_CODE if (RISCV && !RISCV_HAS_CLIC)
+	default IRQ_VECTOR_TABLE_JUMP_BY_CODE if DSPIC
 	default IRQ_VECTOR_TABLE_JUMP_BY_ADDRESS
 
 config IRQ_VECTOR_TABLE_JUMP_BY_ADDRESS
diff --git a/arch/dspic/core/isr_wrapper.S b/arch/dspic/core/isr_wrapper.S
@@ -16,25 +16,25 @@
     .type __COMMONInterrupt,@function
 __COMMONInterrupt:
     .section .isr.text._COMMONInterrupt,keep,code,keep
+    mov.sl #__irq_vector_table+4, w0
+    subr.l w0, [--w15], w0
+    lsr w0, #2, w0
     lnk #0x4
     /* Handle ISR calls and clear handles IRQ
      */
     mov.l w8, [w15++]
     mov.sl #__kernel + ___cpu_t_nested_OFFSET,w8
     add.l [w8],#1,[w8]
-    mov.w _INTTREGbits,w0
-    and.l #0x1ff,w0
-    sub.l w0,#9,w0
+
+    mov.l w0, [w15++]
     mov.sl #__sw_isr_table,w1
     sl.l w0,#3,w0
     add.l w0,w1,w2
     mov.l [w2+4],w1
     mov.l [w2],w0
 
     call	w1
-    mov.w _INTTREGbits,w0
-    and.l #0x1ff,w0
-    sub.l w0,#9,w0
+    mov.l [--w15], w0
     call	_arch_dspic_irq_clear
 
     /* Check and perform context switch
diff --git a/arch/dspic/core/vector_table.S b/arch/dspic/core/vector_table.S
@@ -29,3 +29,8 @@ __vector_table:
     .long __MathErrorTrap
     .long __GeneralTrap
     .long __ReservedTrap7
+    .set offset, 0
+    .rept CONFIG_NUM_IRQS
+        .pword __irq_vector_table + offset
+        .set offset, offset + 4
+    .endr
diff --git a/arch/dspic/include/kernel_arch_swap_macro.S b/arch/dspic/include/kernel_arch_swap_macro.S
@@ -271,9 +271,6 @@
 .endm
 
 .macro z_dspic_do_swap
-    /* Set the SPLIM to end of RAM
-     * To avoid, stack overflow fault.
-     */
 	/* Switch to context 0 before starting context save and restore
 	 * This Arch has 7 context and each has banked register sets for w0-w8
 	 * So in interrupt we are in ctx 1 and need to go to ctx 0 for tasks
diff --git a/boards/microchip/dspic33/dspic33a_curiosity/board.c b/boards/microchip/dspic33/dspic33a_curiosity/board.c
@@ -6,6 +6,8 @@
 #include <zephyr/init.h>
 #include <zephyr/kernel.h>
 
+/* Board level init for dspic33a_curiosity
+ */
 void board_early_init_hook(void)
 {
 }
diff --git a/boards/microchip/dspic33/dspic33a_curiosity/doc/index.rst b/boards/microchip/dspic33/dspic33a_curiosity/doc/index.rst
@@ -130,6 +130,39 @@ Building
 
       west build -p always -b dspic33a_curiosity/<qualifier> samples/hello_world/ -- -DZEPHYR_TOOLCHAIN_VARIANT=xcdsc -DXCDSC_TOOLCHAIN_PATH=/opt/microchip/xc-dsc/<version>
 
+Optimizations
+-------------
+
+The XC-DSC toolchain hooks its optimization levels in
+``cmake/compiler/xcdsc/compiler_flags.cmake`` by mapping Zephyr's generic
+properties to concrete compiler flags. In this file:
+
+* ``optimization_speed`` uses ``-O2``.
+* ``optimization_size`` uses ``-O2``.
+* ``optimization_size_aggressive`` uses ``-Os``.
+* ``optimization_debug`` uses ``-O1``.
+
+In general, :kconfig:option:`CONFIG_SIZE_OPTIMIZATIONS` is enabled in the base
+configuration, so Zephyr picks ``optimization_size`` and therefore ``-O2`` for
+every ``west build`` unless you override the setting in your **application
+prj.conf** (the configuration that sits inside your sample or app directory,
+not a global project file).
+
+To change that default, set one of these options in your application's
+``prj.conf`` and rebuild:
+
+- ``CONFIG_SIZE_OPTIMIZATIONS`` (Zephyr default) keeps the ``-O2`` size profile.
+- ``CONFIG_SIZE_OPTIMIZATIONS_AGGRESSIVE`` switches to ``optimization_size_aggressive``,
+  which adds the ``-Os`` mapping described in ``compiler_flags.cmake``. This
+  level is only available when your XC-DSC compiler is licensed.
+- ``CONFIG_SPEED_OPTIMIZATIONS`` selects ``optimization_speed`` (``-O2``).
+- ``CONFIG_DEBUG_OPTIMIZATIONS`` selects ``optimization_debug`` (``-O1``).
+- ``CONFIG_NO_OPTIMIZATIONS`` forces (``-O0``).
+
+After saving the desired configuration in your application's ``prj.conf``, rerun
+``west build`` and the build system will regenerate all XC-DSC command lines
+with the matching optimization level, no edits to the CMake files are required.
+
 Flashing
 ========
 #. Run your favorite terminal program to listen for output.
diff --git a/cmake/compiler/xcdsc/compiler_flags.cmake b/cmake/compiler/xcdsc/compiler_flags.cmake
@@ -2,10 +2,10 @@
 set_compiler_property(PROPERTY debug -g)
 # Optimization for debug builds
 set_compiler_property(PROPERTY optimization_debug -O1)
-set_compiler_property(PROPERTY optimization_speed -O1)
+set_compiler_property(PROPERTY optimization_speed -O2)
 # Optimize for size
-set_compiler_property(PROPERTY optimization_size -O1)
-set_compiler_property(PROPERTY optimization_size_aggressive -O1)
+set_compiler_property(PROPERTY optimization_size -O2)
+set_compiler_property(PROPERTY optimization_size_aggressive -Os)
 # Basic warnings
 check_set_compiler_property(PROPERTY warning_base -Wall -Wformat -Wformat-security -Wno-format-zero-length -Wno-unused-but-set-variable )
 # Compiler flags for imacros. The specific header must be appended by user.
diff --git a/doc/hardware/arch/dspic33a.rst b/doc/hardware/arch/dspic33a.rst
@@ -15,6 +15,18 @@ Microchip Technology featuring a high-performance 32-bit CPU core with DSP
 capabilities, integrated FPU, and rich peripheral set. The family is designed
 for real-time control applications requiring signal processing capabilities.
 
+dsPIC33A on Zephyr
+******************
+.. image:: ./images/block_diagram.png
+   :align: center          
+
+The dsPIC33A port provides:
+
+- **Board support:** the dsPIC33A Curiosity Platform baseboard (EV74H48A) fitted with either the dsPIC33AK128MC106 or dsPIC33AK512MPS512 DIM modules.
+- **SoC support:** both dsPIC33AK128MC106 (128 KB flash / 16 KB RAM) and dsPIC33AK512MPS512 (512 KB flash / 64 KB RAM) devices.
+- **Driver coverage:** dsPIC33-specific pin control, GPIO, UART console, and system timer drivers.
+- **Basic services:** console output, logging back ends, and idle/power management.
+
 Key supported features
 **********************
 
diff --git a/doc/hardware/arch/images/block_diagram.png b/doc/hardware/arch/images/block_diagram.png
diff --git a/drivers/timer/mchp_dspic33_timer.c b/drivers/timer/mchp_dspic33_timer.c
@@ -96,7 +96,7 @@ void arch_busy_wait(uint32_t usec_to_wait)
 	ARG_UNUSED(usec_to_wait);
 	__asm__ volatile("sl.l w0,#0x03,w0\n\t"
 			 "repeat.w w0\n\t"
-			 "neop\n\n\t");
+			 "nop\n\n\t");
 }
 #endif
 
diff --git a/include/zephyr/arch/dspic/arch.h b/include/zephyr/arch/dspic/arch.h
@@ -26,6 +26,8 @@
 #define DSPIC_IRQ_PER_REG    8u
 #define DSPIC_PRIORITY_MASK  ((1u << DSPIC_PRIORITY_BITS) - 1u)
 
+#define ARCH_IRQ_VECTOR_JUMP_CODE(v) "call _" STRINGIFY(v)
+
 #ifndef _ASMLANGUAGE
 #include <xc.h>
 #ifdef __cplusplus
diff --git a/soc/microchip/dspic33/dspic33a/soc.c b/soc/microchip/dspic33/dspic33a/soc.c
@@ -6,6 +6,8 @@
 #include <zephyr/device.h>
 #include <zephyr/init.h>
 
+/* SOC level init for dspic33a family of chips
+ */
 void soc_early_init_hook(void)
 {
 }

Original file line number	Diff line number	Diff line change
`@@ -6,6 +6,8 @@`
`6`	`6`	`#include <zephyr/init.h>`
`7`	`7`	`#include <zephyr/kernel.h>`
`8`	`8`
	`9`	`+/* Board level init for dspic33a_curiosity`
	`10`	`+ */`
`9`	`11`	`void board_early_init_hook(void)`
`10`	`12`	`{`
`11`	`13`	`}`
Original file line number	Diff line number	Diff line change
`@@ -96,7 +96,7 @@ void arch_busy_wait(uint32_t usec_to_wait)`
`96`	`96`	`ARG_UNUSED(usec_to_wait);`
`97`	`97`	`__asm__ volatile("sl.l w0,#0x03,w0\n\t"`
`98`	`98`	`"repeat.w w0\n\t"`
`99`		`- "neop\n\n\t");`
	`99`	`+ "nop\n\n\t");`
`100`	`100`	`}`
`101`	`101`	`#endif`
`102`	`102`