bricks/simhub: Clean up VM_HOOK.

Also rename desktop target to native for clarity.

Author: laurensvalk

bricks/_common/common.mk

@@ -153,7 +153,7 @@ OPENOCD ?= openocd
 OPENOCD_CONFIG ?= openocd_stm32$(PB_MCU_SERIES_LCASE).cfg
 TEXT0_ADDR ?= 0x08000000
 
-ifeq ($(PB_MCU_FAMILY),desktop)
+ifeq ($(PB_MCU_FAMILY),native)
 UNAME_S := $(shell uname -s)
 LD = $(CC)
 CFLAGS += $(INC) -Wall -Werror -Wdouble-promotion -Wfloat-conversion -std=gnu99 $(COPT) -D_GNU_SOURCE
@@ -163,7 +163,7 @@ else ifeq ($(UNAME_S),Darwin)
 LDFLAGS += -Wl,-map,$@.map -Wl,-dead_strip
 endif
 LIBS =
-else # end desktop, begin embedded
+else # end native, begin embedded
 CROSS_COMPILE ?= arm-none-eabi-
 ifeq ($(PB_MCU_FAMILY),STM32)
 CFLAGS_MCU_F0 = -mthumb -mtune=cortex-m0 -mcpu=cortex-m0 -msoft-float
@@ -250,7 +250,7 @@ PY_EXTRA_SRC_C = $(addprefix shared/,\
 	runtime/stdout_helpers.c \
 	)
 
-ifeq ($(PB_MCU_FAMILY),desktop)
+ifeq ($(PB_MCU_FAMILY),native)
 PY_EXTRA_SRC_C += $(addprefix shared/,\
 	runtime/gchelper_generic.c \
 	)
@@ -286,7 +286,7 @@ PY_EXTRA_SRC_C += $(addprefix bricks/_common/,\
 endif
 
 # Not all MCUs support thumb2 instructions.
-ifeq ($(PB_MCU_FAMILY),desktop)
+ifeq ($(PB_MCU_FAMILY),native)
 SRC_S +=
 else ifeq ($(PB_MCU_SERIES),$(filter $(PB_MCU_SERIES),AT91SAM7 F0 TIAM1808))
 SRC_S += shared/runtime/gchelper_thumb1.s
@@ -587,7 +587,7 @@ CFLAGS += -DMICROPY_MODULE_FROZEN_MPY
 MPY_TOOL_FLAGS += -mlongint-impl none
 endif
 
-ifneq ($(PB_MCU_FAMILY),desktop)
+ifneq ($(PB_MCU_FAMILY),native)
 # Main firmware build targets
 TARGETS := $(BUILD)/firmware.zip
 else

bricks/_common/mpconfigport.h

@@ -149,13 +149,17 @@ typedef long mp_off_t;
 #define MICROPY_END_ATOMIC_SECTION(state) (void)(state)
 #endif
 
-#ifndef MICROPY_VM_HOOK_LOOP
+// Optional extra code to run before MicroPython drives the event loop.
+#ifndef PYBRICKS_VM_HOOK_LOOP_EXTRA
+#define PYBRICKS_VM_HOOK_LOOP_EXTRA
+#endif
+
 #define MICROPY_VM_HOOK_LOOP \
     do { \
+        PYBRICKS_VM_HOOK_LOOP_EXTRA \
         extern bool pbio_os_run_processes_once(void); \
         pbio_os_run_processes_once(); \
     } while (0);
-#endif
 
 #define MICROPY_GC_HOOK_LOOP(i) do { \
         if (((i) & 0xf) == 0) { \

bricks/simhub/Makefile

@@ -2,7 +2,7 @@
 # Copyright (c) 2025 The Pybricks Authors
 
 PBIO_PLATFORM = sim_hub
-PB_MCU_FAMILY = desktop
+PB_MCU_FAMILY = native
 PB_FROZEN_MODULES = 1
 MICROPY_ROM_TEXT_COMPRESSION = 1
 

bricks/simhub/mpconfigport.h

@@ -54,19 +54,30 @@
 #define PYBRICKS_OPT_CUSTOM_IMPORT              (0)
 #define PYBRICKS_OPT_NATIVE_MOD                 (0)
 
+// The Virtual Hub has no hardware interrupt that requests polling every 1ms.
+// We solve this by polling manually as appropriate for the simulation, as
+// indicated below.
 #if PBDRV_CONFIG_CLOCK_TEST
-#define MICROPY_VM_HOOK_LOOP \
+// In the CI variant ("counting clock"), the clock is advanced on every
+// pbio_os_hook_wait_for_interrupt, which is called from mp_hal_delay_ms. But
+// the user could be running a tight loop without any waits. We still want to
+// advance the clock in those cases, which we mimic here by advancing the clock
+// every couple of MicroPython byte codes. This also polls to the event loop.
+#define PYBRICKS_VM_HOOK_LOOP_EXTRA \
     do { \
         static uint32_t count; \
         if ((count % 16) == 0) { \
             extern void pbio_test_clock_tick(uint32_t ticks); \
             pbio_test_clock_tick(1); \
         } \
-        extern bool pbio_os_run_processes_once(void); \
-        pbio_os_run_processes_once(); \
     } while (0);
 #else
-#define MICROPY_VM_HOOK_LOOP \
+// When using the wall clock, time advances automatically but we still need to
+// request polling. This is done at the end of pbio_os_hook_wait_for_interrupt.
+// As above, we also need something to move it along with blocking user loops.
+// Instead of guessing with a number of instructions, here we can just poll
+// whenever the wall clock changes.
+#define PYBRICKS_VM_HOOK_LOOP_EXTRA \
     do { \
         static uint32_t clock_last; \
         extern uint32_t pbdrv_clock_get_ms(void); \
@@ -76,8 +87,6 @@
             pbio_os_request_poll(); \
             clock_last = clock_now; \
         } \
-        extern bool pbio_os_run_processes_once(void); \
-        pbio_os_run_processes_once(); \
     } while (0);
 #endif
 

bricks/simhub/pbio_os_hook.c

@@ -11,38 +11,38 @@
 
 #if PBDRV_CONFIG_CLOCK_TEST
 #include <pbdrv/../../drv/clock/clock_test.h>
-#endif
 
 pbio_os_irq_flags_t pbio_os_hook_disable_irq(void) {
     sigset_t sigmask;
-
-    #if PBDRV_CONFIG_CLOCK_TEST
     sigemptyset(&sigmask);
     return sigmask;
-    #endif
+}
+
+void pbio_os_hook_enable_irq(pbio_os_irq_flags_t flags) {
+}
 
+void pbio_os_hook_wait_for_interrupt(pbio_os_irq_flags_t flags) {
+    // All events have been handled at this time. Advance the clock
+    // and continue immediately.
+    pbio_test_clock_tick(1);
+}
+
+#else
+
+pbio_os_irq_flags_t pbio_os_hook_disable_irq(void) {
+    sigset_t sigmask;
     sigfillset(&sigmask);
     sigset_t origmask;
     pthread_sigmask(SIG_SETMASK, &sigmask, &origmask);
     return origmask;
 }
 
 void pbio_os_hook_enable_irq(pbio_os_irq_flags_t flags) {
-    #if PBDRV_CONFIG_CLOCK_TEST
-    return;
-    #endif
-
     sigset_t origmask = (sigset_t)flags;
     pthread_sigmask(SIG_SETMASK, &origmask, NULL);
 }
 
 void pbio_os_hook_wait_for_interrupt(pbio_os_irq_flags_t flags) {
-    #if PBDRV_CONFIG_CLOCK_TEST
-    // All events have been handled at this time. Advance the clock
-    // and continue immediately.
-    pbio_test_clock_tick(1);
-    return;
-    #endif
 
     struct timespec timeout = {
         .tv_sec = 0,
@@ -57,3 +57,5 @@ void pbio_os_hook_wait_for_interrupt(pbio_os_irq_flags_t flags) {
     // There is a new timer event to handle.
     pbio_os_request_poll();
 }
+
+#endif