MULAB is 32 bit (16 bit * 16 bit)

Author: smokku

src/chips/ria816.c

@@ -73,9 +73,11 @@ uint8_t ria816_reg_read(ria816_t* c, uint8_t addr) {
     switch (addr) {
         // multiplication accelerator
         case RIA816_MATH_MULAB:
-        case RIA816_MATH_MULAB + 1: {
-            uint16_t mul = RIA816_REG16(c->reg, RIA816_MATH_OPERA) * RIA816_REG16(c->reg, RIA816_MATH_OPERB);
-            data = (addr == RIA816_MATH_MULAB) ? (mul & 0xFF) : (mul >> 8);
+        case RIA816_MATH_MULAB + 1:
+        case RIA816_MATH_MULAB + 2:
+        case RIA816_MATH_MULAB + 3: {
+            uint32_t mul = RIA816_REG16(c->reg, RIA816_MATH_OPERA) * RIA816_REG16(c->reg, RIA816_MATH_OPERB);
+            data = ((uint8_t*)&mul)[addr & 0x03];
         } break;
         // division accelerator
         case RIA816_MATH_DIVAB:

src/chips/ria816.h

@@ -128,8 +128,8 @@ extern "C" {
 #define RIA816_MATH_OPERA     (0x00)  // Operand A for multiplication and division.
 #define RIA816_MATH_OPERB     (0x02)  // Operand B for multiplication and division.
 #define RIA816_MATH_MULAB     (0x04)  // OPERA * OPERB.
-#define RIA816_MATH_DIVAB     (0x06)  // Signed OPERA / unsigned OPERB.
-#define RIA816_TIME_TM        (0x08)  // Time Of Day (ms) - 48bits (6 bytes)
+#define RIA816_MATH_DIVAB     (0x08)  // Signed OPERA / unsigned OPERB.
+#define RIA816_TIME_TM        (0x0A)  // Time Of Day (ms) - 48bits (6 bytes)
 #define RIA816_DMA_ADDRSRC    (0x10)  // DMA source address.
 #define RIA816_DMA_STEPSRC    (0x13)  // DMA source step.
 #define RIA816_DMA_ADDRDST    (0x14)  // DMA destination address.