From 15a0bf120a4564642eb380575054cc5a0793aa98 Mon Sep 17 00:00:00 2001
From: Connor Olding <cloningdonor@gmail.com>
Date: Sat, 29 Sep 2018 07:05:33 +0200
Subject: [PATCH] improve wait macros

---
 debug.asm       | 12 ++++++------
 inc/64drive.inc |  2 ++
 inc/n64_pi.inc  |  4 ++--
 3 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/debug.asm b/debug.asm
index cc29fc7..04b7a26 100644
--- a/debug.asm
+++ b/debug.asm
@@ -46,10 +46,10 @@ Drive64Write:
     // set length (needs to be decremented due to DMA quirk)
     subiu   t3, a3, 1
 
-    PI_WAIT()
-    sw      t1, PI_DRAM_ADDR(t5)
-    sw      t2, PI_CART_ADDR(t5)
-    sw      t3, PI_RD_LEN(t5)  // "read" from DRAM to cart
+    PI_WAIT() // clobbers a0,t0
+    sw      t1, PI_DRAM_ADDR(a0)
+    sw      t2, PI_CART_ADDR(a0)
+    sw      t3, PI_RD_LEN(a0)  // "read" from DRAM to cart
     PI_WAIT()
 
 Drive64WriteDirect: // TODO: rewrite so this takes a0,a1 instead of a2,a3
@@ -66,7 +66,7 @@ Drive64WriteDirect: // TODO: rewrite so this takes a0,a1 instead of a2,a3
     lui     t9, K_BASE
     lw      t9, K_CI_BASE(t9)
 
-    CI_USB_WRITE_WAIT(0x10000) // clobbers t0,v0, requires t9
+    CI_USB_WRITE_WAIT(0x10000) // clobbers a0,v0,t0, requires t9
     bnez    v0, Drive64WriteExit
     nop
 
@@ -76,7 +76,7 @@ Drive64WriteDirect: // TODO: rewrite so this takes a0,a1 instead of a2,a3
     PI_WAIT()
     sw      t1, CI_USB_COMMAND_STATUS(t9)
 
-    CI_USB_WRITE_WAIT(0x10000) // clobbers t0,v0, requires t9
+    CI_USB_WRITE_WAIT(0x10000) // clobbers a0,v0,t0, requires t9
 
 Drive64WriteExit:
     jr      ra
diff --git a/inc/64drive.inc b/inc/64drive.inc
index 9f165b9..41591e1 100644
--- a/inc/64drive.inc
+++ b/inc/64drive.inc
@@ -34,6 +34,7 @@ constant CI_EEPROM($1000)               // 2048 bytes
 constant CI_WRITEBACK_LBA($1800)        // 1024 bytes (256 words)
 
 macro CI_WAIT() {
+    // requires t9 to be set to either CI_BASE or CI_BASE_EXTENDED
     PI_WAIT()
 -
     lw      t0, CI_STATUS(t9)
@@ -43,6 +44,7 @@ macro CI_WAIT() {
 }
 
 macro CI_USB_WRITE_WAIT(timeout) {
+    // requires t9 to be set to either CI_BASE or CI_BASE_EXTENDED
     PI_WAIT()
 
     if {timeout} > 0 {
diff --git a/inc/n64_pi.inc b/inc/n64_pi.inc
index aa47ba3..cfd7f15 100644
--- a/inc/n64_pi.inc
+++ b/inc/n64_pi.inc
@@ -14,9 +14,9 @@ constant PI_BSD_DOM2_PGS($2C) // $0460002C Domain 2 Page Size
 constant PI_BSD_DOM2_RLS($30) // $04600030 Domain 2 Release
 
 macro PI_WAIT() {
-    lui     t5, PI_BASE
+    lui     a0, PI_BASE
 -
-    lw      t0, PI_STATUS(t5)
+    lw      t0, PI_STATUS(a0)
     andi    t0, t0, 3
     bnez    t0,-
     nop