First working RX ISR

Makefile

@@ -1,6 +1,7 @@
 PSXSDK_DIR = /usr/local/psxsdk
 
 AS = mipsel-unknown-elf-as
+AS_FLAGS = -msoft-float
 CC = mipsel-unknown-elf-gcc
 DEFINE = -DVIDEO_MODE=VMODE_PAL -D__PSXSDK__ -fno-strict-overflow -fsigned-char -msoft-float -mno-gpopt -fno-builtin -g
 LIBS = -lfixmath

include/reception.h

@@ -0,0 +1,7 @@
+#ifndef RECEPTION_H
+#define RECEPTION_H
+
+void reception_ev(void);
+void reception_loop(void);
+
+#endif /* RECEPTION_H */

src/Serial.c

@@ -7,106 +7,93 @@
 #include <psx.h>
 #include <stddef.h>
 
-static volatile size_t isr_calls;
+enum
+{
+    FIFO_SZ = 128
+};
+
+typedef volatile struct
+{
+    unsigned char buf[FIFO_SZ];
+    size_t pending, processed;
+    bool full;
+} fifo;
+
+static fifo rx;
 
 void sio_handler_callback(void)
 {
-    printf("%s\n", __func__);
-    isr_calls++;
+    while (SIOCheckInBuffer())
+    {
+        const unsigned char in = SIOReadByte();
+        size_t aux = rx.pending;
+
+        if (++aux >= (sizeof rx.buf / sizeof *rx.buf))
+            aux = 0;
+
+        if (aux != rx.processed)
+        {
+            rx.buf[aux] = in;
+            rx.pending = rx.processed;
+        }
+        else
+        {
+            rx.full = true;
+        }
+    }
+
+    SIOAcknowledgeInterrupt();
 }
 
 void SerialInit(void)
 {
-    int *sio_handler(void);
+    enum
+    {
+        SPEC_COUNTER_BECOMES_ZERO = 0x0001,
+        SPEC_INTERRUPTED = 0x0002,
+        SPEC_EOF = 0x0004,
+        SPEC_FILE_WAS_CLOSED = 0x0008,
+        SPEC_CMD_ACK = 0x0010,
+        SPEC_CMD_COMPLETED = 0x0020,
+        SPEC_DATA_READY = 0x0040,
+        SPEC_DATA_END = 0x0080,
+        SPEC_TIMEOUT = 0x0100,
+        SPEC_UNKNOWN_CMD = 0x0200,
+        SPEC_END_READ_BUFFER = 0x0400,
+        SPEC_END_WRITE_BUFFER = 0x0800,
+        SPEC_GENERAL_INTERRUPT = 0x1000,
+        SPEC_NEW_DEVICE = 0x2000,
+        SPEC_SYS_CALL_INSTR = 0x4000,
+        SPEC_ERROR = 0x8000,
+        SPEC_PREV_WRITE_ERROR = 0x8001,
+        SPEC_DOMAIN_ERROR_LIBMATH = 0x0301,
+        SPEC_RANGE_ERROR_LIBMATH = 0x0302
+    };
 
     enum
     {
-        SIO_CLASS = 0xF000000B
+        SIO_CLASS = 0xF000000B,
+        TRIGGER_CALLBACK = 0x1000,
+        BAUD_RATE = 115200
     };
 
-    EnterCriticalSection();
+    const int not_crit = EnterCriticalSection();
+    void sio_handler(void);
 
-    IMASK |= 1 << 8;
+    SIOReset();
+    SIOStart(BAUD_RATE);
 
-    const int sio_handle = OpenEvent(SIO_CLASS, 0x1000, 0x1000, sio_handler);
+    const int sio_handle = OpenEvent(SIO_CLASS, SPEC_GENERAL_INTERRUPT, TRIGGER_CALLBACK, sio_handler);
 
     if (sio_handle != 0xFFFFFFFF)
-    {
-        enum
-        {
-            BAUD_RATE = 115200
-        };
-
         EnableEvent(sio_handle);
-        SIOStart(BAUD_RATE);
-        redirect_stdio_to_sio();
-        printf("sio_handle = 0x%08X", sio_handle);
-    }
 
-    ExitCriticalSection();
+    IMASK |= 1 << INT_SIO;
 
-    SIOSendByte('y');
+    SIOEnableRXInterrupt();
 
-    printf("%u\n", isr_calls);
-
-    while (!(IPENDING & (1 << 8)));
-
-    printf("SIO ISR triggered\n");
-}
-
-void SerialRead(uint8_t *ptrArray, size_t nBytes)
-{
-    if (nBytes)
+    if (not_crit)
     {
-        InterruptsDisableInt(INT_SOURCE_VBLANK);
-
-        do
-        {
-            /* Wait for RX FIFO not empty. */
-            while (!SIOCheckInBuffer());
-
-            *(ptrArray++) = SIOReadByte();
-        } while (--nBytes);
-
-        InterruptsEnableInt(INT_SOURCE_VBLANK);
+        ExitCriticalSection();
     }
 }
-
-void SerialWrite(const void* ptrArray, size_t nBytes)
-{
-    if (nBytes)
-    {
-        InterruptsDisableInt(INT_SOURCE_VBLANK);
-        do
-        {
-            /* Wait for TX FIFO empty. */
-            while (!SIOCheckOutBuffer());
-
-            SIOSendByte(*(uint8_t*)ptrArray++);
-
-        } while (--nBytes);
-
-        InterruptsEnableInt(INT_SOURCE_VBLANK);
-    }
-    else
-    {
-    }
-}
-
-#ifdef SERIAL_INTERFACE
-void Serial_printf(const char* const str, ...)
-{
-    va_list ap;
-    int result;
-    static char internal_buffer[SERIAL_PRINTF_INTERNAL_BUFFER_SIZE];
-
-    va_start(ap, str);
-
-    result = vsnprintf( internal_buffer,
-                        SERIAL_PRINTF_INTERNAL_BUFFER_SIZE,
-                        str,
-                        ap  );
-
-    SerialWrite(internal_buffer, result);
-}
-#endif // SERIAL_INTERFACE

src/System.c

@@ -6,6 +6,7 @@
 
 void SystemInit(void)
 {
+	redirect_stdio_to_sio();
 #if 0
 	PSX_InitEx(PSX_INIT_SAVESTATE | PSX_INIT_CD);
 #else

src/main.c

@@ -1,5 +1,5 @@
 #include "System.h"
-#include <stdio.h>
+#include "reception.h"
 
 #define PSX_EXE_HEADER_SIZE 2048
 #define EXE_DATA_PACKET_SIZE 8
@@ -8,7 +8,10 @@ int main(void)
 {
     SystemInit();
 
-    for (;;);
+    reception_loop();
+
+    for (;;)
+        ;
 
 #if 0
     {
@@ -122,5 +125,6 @@ int main(void)
         exeAddress();
     }
 #endif
+
     return 0;
 }

src/reception.c

@@ -0,0 +1,26 @@
+#include "reception.h"
+#include "Serial.h"
+#include <stdbool.h>
+
+static volatile bool rx;
+
+static enum
+{
+
+} state;
+
+void reception_ev(void)
+{
+    rx = true;
+}
+
+void reception_loop(void)
+{
+    for (;;)
+    {
+        if (rx)
+        {
+
+        }
+    }
+}

src/sio.s

@@ -1,94 +0,0 @@
-.extern sio_handler_callback
-.extern sio_handler
-
-sio_handler:
-	addi $sp, -120
-.set noat
-	sw $at, 0($sp)
-	mfhi $at
-	sw $at, 112($sp)
-	mflo $at
-	sw $at, 116($sp)
-.set at
-	sw $v0, 4($sp)
-	sw $v1, 8($sp)
-	sw $a0, 12($sp)
-	sw $a1, 16($sp)
-	sw $a2, 20($sp)
-	sw $a3, 24($sp)
-	sw $t0, 28($sp)
-	sw $t1, 32($sp)
-	sw $t2, 36($sp)
-	sw $t3, 40($sp)
-	sw $t4, 44($sp)
-	sw $t5, 48($sp)
-	sw $t6, 52($sp)
-	sw $t7, 56($sp)
-	sw $s0, 60($sp)
-	sw $s1, 64($sp)
-	sw $s2, 68($sp)
-	sw $s3, 72($sp)
-	sw $s4, 76($sp)
-	sw $s5, 80($sp)
-	sw $s6, 84($sp)
-	sw $s7, 88($sp)
-	sw $t8, 92($sp)
-	sw $t9, 96($sp)
-	sw $gp, 100($sp)
-	sw $s8, 104($sp)
-
-	la $t0, sio_handler_callback
-	lw $t1, 0($t0)
-
-	addiu $sp, $sp, -24
-	jalr $t1
-	nop
-	addiu $sp, $sp, 24
-
-	li $t0, 0x1f801070 # IPENDING
-
-	lw $t1, 0($t0)
-	nop
-	nop
-	xori $t1, $t1, 0x100 # Acknowledge SIO IRQ
-	sw $t1, 0($t0)
-
-.set noat
-	lw $at, 112($sp)
-	nop
-	mthi $at
-	lw $at, 116($sp)
-	nop
-	mtlo $at
-	lw $at, 0($sp)
-.set at
-	lw $v0, 4($sp)
-	lw $v1, 8($sp)
-	lw $a0, 12($sp)
-	lw $a1, 16($sp)
-	lw $a2, 20($sp)
-	lw $a3, 24($sp)
-	lw $t0, 28($sp)
-	lw $t1, 32($sp)
-	lw $t2, 36($sp)
-	lw $t3, 40($sp)
-	lw $t4, 44($sp)
-	lw $t5, 48($sp)
-	lw $t6, 52($sp)
-	lw $t7, 56($sp)
-	lw $s0, 60($sp)
-	lw $s1, 64($sp)
-	lw $s2, 68($sp)
-	lw $s3, 72($sp)
-	lw $s4, 76($sp)
-	lw $s5, 80($sp)
-	lw $s6, 84($sp)
-	lw $s7, 88($sp)
-	lw $t8, 92($sp)
-	lw $t9, 96($sp)
-	lw $gp, 100($sp)
-	lw $s8, 104($sp)
-	lw $ra, 108($sp)
-	addi $sp, 120
-	jr $ra
-	nop