Implemented, but crashing

f3dex3.s

@@ -914,6 +914,9 @@ G_LIGHTTORDP_handler:
 vertex_end:
 tri_end:
 .endif
+.if CFG_LEGACY_VTX_PIPE
+G_MEMSET_handler:
+.endif
 G_SPNOOP_handler:
 run_next_DL_command:
      mfc0   $1, SP_STATUS                               // load the status word into register $1
@@ -3348,7 +3351,7 @@ ovl234_lighting_entrypoint_ovl4ver:        // same IMEM address as ovl234_lighti
 // Jump here for all overlay 4 features. If overlay 4 is loaded (this code), jumps
 // to the instruction selection below.
 ovl234_ovl4_entrypoint:
-.if !CFG_LEGACY_VTX_PIPE && !CFG_NO_OCCLUSION_PLANE
+.if !CFG_NO_OCCLUSION_PLANE
 G_MTX_end:
 .endif
 .if CFG_PROFILING_B
@@ -3428,7 +3431,7 @@ g_memset_real:
 memsetBufferStart equ ((vertexBuffer + 0xF) & 0xFF0)
 memsetBufferEnd equ (clipTempVertsEnd & 0xFF0)
 memsetBufferSize equ (memsetBufferEnd - memsetBufferStart)
-    llv     $v2[0], rdpHalf1Val         // Load the memset value
+    llv     $v2[0], (rdpHalf1Val)($zero) // Load the memset value
     sll     cmd_w0, cmd_w0, 8           // Clear upper byte
     jal     segmented_to_physical
      srl    cmd_w0, cmd_w0, 8           // Number of bytes to memset (must be mult of 16)
@@ -3448,7 +3451,7 @@ memsetBufferSize equ (memsetBufferEnd - memsetBufferStart)
     sub     cmd_w0, cmd_w0, $2
     bgtz    cmd_w0, @@transaction_loop
      add    cmd_w1_dram, cmd_w1_dram, $2
-    jr      $ra
+    j       wait_for_dma_and_run_next_command
      // Delay slot harmless
 clamp_to_memset_buffer:
     addi    $11, cmd_w0, -memsetBufferSize // Is more than a whole buffer left?

gbi.h

@@ -44,6 +44,7 @@ of warnings if you use -Wpedantic. */
 /*#define G_SPECIAL_3       0xD3  no-op in F3DEX2 */
 /*#define G_SPECIAL_2       0xD4  no-op in F3DEX2 */
 /*#define G_SPECIAL_1       0xD5  triggered MVP recalculation, not supported in F3DEX3 */
+#define G_MEMSET            0xD5
 #define G_DMA_IO            0xD6
 #define G_TEXTURE           0xD7
 #define G_POPMTX            0xD8
@@ -2384,6 +2385,22 @@ _DW({                                               \
 #define gSPDmaWrite(pkt,dmem,dram,size) gSPDma_io((pkt),1,(dmem),(dram),(size))
 #define gsSPDmaWrite(dmem,dram,size)    gsSPDma_io(     1,(dmem),(dram),(size))
 
+/**
+ * Use RSP DMAs to set a region of memory to a repeated 16-bit value. This can
+ * clear the color framebuffer or Z-buffer faster than the RDP can in fill mode.
+ * dram: Segmented or physical start address. Must be aligned to 16 bytes.
+ * value: 16-bit value to fill the memory with. e.g. 0 for color, 0xFFFC for Z.
+ * size: Size in bytes to fill, must be nonzero and a multiple of 16 bytes.
+ */
+#define gSPMemset(pkt, dram, value, size)               \
+_DW({                                                   \
+    gImmp1(pkt, G_RDPHALF_1, ((value) & 0xFFFF));       \
+    gDma0p(pkt, G_MEMSET, (dram), ((size) & 0xFFFFF0)); \
+})
+
+#define gsSPMemset(pkt, dram, value, size)    \
+    gsImmp1(G_RDPHALF_1, ((value) & 0xFFFF)), \
+    gsDma0p(G_MEMSET, (dram), ((size) & 0xFFFFF0))
 
 /*
  * RSP short command (no DMA required) macros