From 28b60fc00cd13f9e4780b88cddbad4b4f2be4cca Mon Sep 17 00:00:00 2001
From: Tharo <17233964+Thar0@users.noreply.github.com>
Date: Sat, 16 Aug 2025 14:07:25 +0100
Subject: [PATCH] Handwritten asm: bcmp, bcopy, bzero (#1817)

* Handwritten asm: bcmp, bcopy, bzero

* consistent and

* Consistent add
---
 Makefile                  |   2 +
 spec/spec                 |   6 +-
 src/libultra/libc/bcmp.s  |  89 ++++++++++++++++
 src/libultra/libc/bcopy.s | 211 ++++++++++++++++++++++++++++++++++++++
 src/libultra/libc/bzero.s |  59 +++++++++++
 5 files changed, 364 insertions(+), 3 deletions(-)
 create mode 100644 src/libultra/libc/bcmp.s
 create mode 100644 src/libultra/libc/bcopy.s
 create mode 100644 src/libultra/libc/bzero.s

diff --git a/Makefile b/Makefile
index 9db3585703..c569f8d878 100644
--- a/Makefile
+++ b/Makefile
@@ -447,6 +447,8 @@ $(BUILD_DIR)/src/libultra/libc/%.o: OPTFLAGS := -O2
 $(BUILD_DIR)/src/libultra/gu/%.o: OPTFLAGS := -O2
 $(BUILD_DIR)/src/libultra/rmon/%.o: OPTFLAGS := -O2
 
+$(BUILD_DIR)/src/libultra/libc/%.o: ASOPTFLAGS := -O2
+
 $(BUILD_DIR)/src/boot/libu64/%.o: OPTFLAGS := -O2
 
 $(BUILD_DIR)/src/boot/libc/%.o: OPTFLAGS := -O2
diff --git a/spec/spec b/spec/spec
index 3ad80ab38e..c477c58463 100644
--- a/spec/spec
+++ b/spec/spec
@@ -69,7 +69,7 @@ beginseg
     include "$(BUILD_DIR)/src/libultra/os/thread.o"
     include "$(BUILD_DIR)/src/libultra/os/destroythread.o"
     include "$(BUILD_DIR)/src/libultra/voice/voicecheckresult.o"
-    include "$(BUILD_DIR)/asm/boot/bzero.text.o"
+    include "$(BUILD_DIR)/src/libultra/libc/bzero.o"
     include "$(BUILD_DIR)/src/libultra/io/motor.o"
     include "$(BUILD_DIR)/src/libultra/io/siacs.o"
     include "$(BUILD_DIR)/src/libultra/io/controller.o"
@@ -140,7 +140,7 @@ beginseg
     include "$(BUILD_DIR)/src/libultra/gu/position.o"
     include "$(BUILD_DIR)/src/libultra/io/epirawdma.o"
     include "$(BUILD_DIR)/src/libultra/io/sptaskyielded.o"
-    include "$(BUILD_DIR)/asm/boot/bcmp.text.o"
+    include "$(BUILD_DIR)/src/libultra/libc/bcmp.o"
     include "$(BUILD_DIR)/src/libultra/os/gettime.o"
     include "$(BUILD_DIR)/src/libultra/gu/rotate.o"
     include "$(BUILD_DIR)/src/libultra/os/setglobalintmask.o"
@@ -157,7 +157,7 @@ beginseg
     include "$(BUILD_DIR)/src/libultra/os/getcompare.o"
     include "$(BUILD_DIR)/src/libultra/io/dpgetstat.o"
     include "$(BUILD_DIR)/src/libultra/io/dpsetstat.o"
-    include "$(BUILD_DIR)/asm/boot/bcopy.text.o"
+    include "$(BUILD_DIR)/src/libultra/libc/bcopy.o"
     include "$(BUILD_DIR)/src/libultra/os/resetglobalintmask.o"
     include "$(BUILD_DIR)/src/libultra/io/pfsdeletefile.o"
     include "$(BUILD_DIR)/src/libultra/gu/ortho.o"
diff --git a/src/libultra/libc/bcmp.s b/src/libultra/libc/bcmp.s
new file mode 100644
index 0000000000..dab1c2c672
--- /dev/null
+++ b/src/libultra/libc/bcmp.s
@@ -0,0 +1,89 @@
+#include "PR/asm.h"
+#include "PR/regdef.h"
+
+.text
+
+LEAF(bcmp)
+    xor     v0, a0, a1
+    blt     a2, 0x10, bytecmp
+
+    and     v0, v0, 3
+    negu    t8, a0
+    bnez    v0, unaligncmp
+
+    and     t8, t8, 3
+    subu    a2, a2, t8
+    beqz    t8, wordcmp
+
+    move    v0, v1
+    lwl     v0, (a0)
+    lwl     v1, (a1)
+    addu    a0, a0, t8
+    addu    a1, a1, t8
+    bne     v0, v1, cmpne
+
+wordcmp:
+    and     a3, a2, ~3
+    subu    a2, a2, a3
+    beqz    a3, bytecmp
+
+    addu    a3, a3, a0
+1:
+    lw      v0, (a0)
+    lw      v1, (a1)
+    addu    a0, a0, 4
+    addu    a1, a1, 4
+    bne     v0, v1, cmpne
+    bne     a0, a3, 1b
+
+    b       bytecmp
+
+unaligncmp:
+    negu    a3, a1
+    and     a3, a3, 3
+    subu    a2, a2, a3
+    beqz    a3, partaligncmp
+
+    addu    a3, a3, a0
+1:
+    lbu     v0, (a0)
+    lbu     v1, (a1)
+    addu    a0, a0, 1
+    addu    a1, a1, 1
+    bne     v0, v1, cmpne
+    bne     a0, a3, 1b
+
+partaligncmp:
+    and     a3, a2, ~3
+    subu    a2, a2, a3
+    beqz    a3, bytecmp
+
+    addu    a3, a3, a0
+1:
+    lwl     v0, (a0)
+    lwr     v0, 3(a0)
+    lw      v1, (a1)
+    addu    a0, a0, 4
+    addu    a1, a1, 4
+    bne     v0, v1, cmpne
+    bne     a0, a3, 1b
+
+bytecmp:
+    addu    a3, a2, a0
+    blez    a2, cmpdone
+1:
+    lbu     v0, (a0)
+    lbu     v1, (a1)
+    addu    a0, a0, 1
+    addu    a1, a1, 1
+    bne     v0, v1, cmpne
+    bne     a0, a3, 1b
+
+cmpdone:
+    move    v0, zero
+    jr      ra
+
+cmpne:
+    li      v0, 1
+    jr      ra
+END(bcmp)
diff --git a/src/libultra/libc/bcopy.s b/src/libultra/libc/bcopy.s
new file mode 100644
index 0000000000..3c0742048e
--- /dev/null
+++ b/src/libultra/libc/bcopy.s
@@ -0,0 +1,211 @@
+#include "PR/asm.h"
+#include "PR/regdef.h"
+
+.text
+
+LEAF(bcopy)
+    move    a3, a1
+    beqz    a2, ret
+    beq     a0, a1, ret
+    blt     a1, a0, goforwards
+    add     v0, a0, a2
+    bge     a1, v0, goforwards
+    b       gobackwards
+
+goforwards:
+    blt     a2, 0x10, forwards_bytecopy
+    and     v0, a0, 3
+    and     v1, a1, 3
+    beq     v0, v1, forwalignable
+
+forwards_bytecopy:
+    beqz    a2, ret
+    addu    v1, a0, a2
+99:
+    lb      v0, (a0)
+    addu    a0, a0, 1
+    sb      v0, (a1)
+    addu    a1, a1, 1
+    bne     a0, v1, 99b
+ret:
+    move    v0, a3
+    jr      ra
+
+forwalignable:
+    beqz    v0, forwards_32
+    beq     v0, 1, forw_copy3
+    beq     v0, 2, forw_copy2
+
+    lb      v0, (a0)
+    addu    a0, a0, 1
+    sb      v0, (a1)
+    addu    a1, a1, 1
+    addu    a2, a2, -1
+    b       forwards_32
+
+forw_copy2:
+    lh      v0, (a0)
+    addu    a0, a0, 2
+    sh      v0, (a1)
+    addu    a1, a1, 2
+    addu    a2, a2, -2
+    b       forwards_32
+
+forw_copy3:
+    lb      v0, (a0)
+    lh      v1, 1(a0)
+    addu    a0, a0, 3
+    sb      v0, (a1)
+    sh      v1, 1(a1)
+    addu    a1, a1, 3
+    addu    a2, a2, -3
+
+forwards:
+forwards_32:
+    blt     a2, 32, forwards_16
+    lw      v0, 0(a0)
+    lw      v1, 4(a0)
+    lw      t0, 8(a0)
+    lw      t1, 12(a0)
+    lw      t2, 16(a0)
+    lw      t3, 20(a0)
+    lw      t4, 24(a0)
+    lw      t5, 28(a0)
+    addu    a0, a0, 32
+    sw      v0, 0(a1)
+    sw      v1, 4(a1)
+    sw      t0, 8(a1)
+    sw      t1, 12(a1)
+    sw      t2, 16(a1)
+    sw      t3, 20(a1)
+    sw      t4, 24(a1)
+    sw      t5, 28(a1)
+    addu    a1, a1, 32
+    addu    a2, a2, -32
+    b       forwards_32
+
+forwards_16:
+    blt     a2, 16, forwards_4
+    lw      v0, 0(a0)
+    lw      v1, 4(a0)
+    lw      t0, 8(a0)
+    lw      t1, 12(a0)
+    addu    a0, a0, 16
+    sw      v0, 0(a1)
+    sw      v1, 4(a1)
+    sw      t0, 8(a1)
+    sw      t1, 12(a1)
+    addu    a1, a1, 16
+    addu    a2, a2, -16
+    b       forwards_16
+
+forwards_4:
+    blt     a2, 4, forwards_bytecopy
+
+    lw      v0, 0(a0)
+    addu    a0, a0, 4
+    sw      v0, 0(a1)
+    addu    a1, a1, 4
+    addu    a2, a2, -4
+    b       forwards_4
+
+gobackwards:
+    add     a0, a0,a2
+    add     a1, a1,a2
+    blt     a2, 16, backwards_bytecopy
+
+    and     v0, a0, 0x3
+    and     v1, a1, 0x3
+    beq     v0, v1, backalignable
+
+backwards_bytecopy:
+    beqz    a2, ret
+    addu    a0, a0, -1
+    addu    a1, a1, -1
+    subu    v1, a0,a2
+99:
+    lb      v0, 0(a0)
+    addu    a0, a0, -1
+    sb      v0, 0(a1)
+    addu    a1, a1, -1
+    bne     a0, v1,99b
+
+    move    v0, a3
+    jr      ra
+
+backalignable:
+    beqz    v0, backwards
+    beq     v0, 3, back_copy3
+    beq     v0, 2, back_copy2
+    lb      v0, -1(a0)
+    addu    a0, a0, -1
+    sb      v0, -1(a1)
+    addu    a1, a1, -1
+    addu    a2, a2, -1
+    b       backwards
+
+back_copy2:
+    lh      v0, -2(a0)
+    addu    a0, a0, -2
+    sh      v0, -2(a1)
+    addu    a1, a1, -2
+    addu    a2, a2, -2
+    b       backwards
+
+back_copy3:
+    lb      v0, -1(a0)
+    lh      v1, -3(a0)
+    addu    a0, a0, -3
+    sb      v0, -1(a1)
+    sh      v1, -3(a1)
+    addu    a1, a1, -3
+    addu    a2, a2, -3
+
+backwards:
+backwards_32:
+    blt     a2, 32, backwards_16
+    lw      v0, -4(a0)
+    lw      v1, -8(a0)
+    lw      t0, -12(a0)
+    lw      t1, -16(a0)
+    lw      t2, -20(a0)
+    lw      t3, -24(a0)
+    lw      t4, -28(a0)
+    lw      t5, -32(a0)
+    addu    a0, a0, -32
+    sw      v0, -4(a1)
+    sw      v1, -8(a1)
+    sw      t0, -12(a1)
+    sw      t1, -16(a1)
+    sw      t2, -20(a1)
+    sw      t3, -24(a1)
+    sw      t4, -28(a1)
+    sw      t5, -32(a1)
+    addu    a1, a1, -32
+    addu    a2, a2, -32
+    b       backwards_32
+
+backwards_16:
+    blt     a2, 16, backwards_4
+    lw      v0, -4(a0)
+    lw      v1, -8(a0)
+    lw      t0, -12(a0)
+    lw      t1, -16(a0)
+    addu    a0, a0, -16
+    sw      v0, -4(a1)
+    sw      v1, -8(a1)
+    sw      t0, -12(a1)
+    sw      t1, -16(a1)
+    addu    a1, a1, -16
+    addu    a2, a2, -16
+    b       backwards_16
+
+backwards_4:
+    blt     a2, 4, backwards_bytecopy
+    lw      v0, -4(a0)
+    addu    a0, a0, -4
+    sw      v0, -4(a1)
+    addu    a1, a1, -4
+    addu    a2, a2, -4
+    b       backwards_4
+END(bcopy)
diff --git a/src/libultra/libc/bzero.s b/src/libultra/libc/bzero.s
new file mode 100644
index 0000000000..84f305fca8
--- /dev/null
+++ b/src/libultra/libc/bzero.s
@@ -0,0 +1,59 @@
+#include "PR/asm.h"
+#include "PR/regdef.h"
+
+.text
+
+LEAF(bzero)
+    negu    v1, a0
+    blt     a1, 0xC, bytezero
+
+    and     v1, v1, 3
+    subu    a1, a1, v1
+    beqz    v1, blkzero
+
+    swl     zero, (a0)
+    addu    a0, a0, v1
+blkzero:
+    /* align backwards to 0x20 */
+    and     a3, a1, ~(0x20 - 1)
+    /* If the result is zero, the amount to zero is less than 0x20 bytes */
+    subu    a1, a1, a3
+    beqz    a3, wordzero
+    /* zero in blocks of 0x20 at a time */
+    addu    a3, a3, a0
+1:
+    sw      zero, 0(a0)
+    sw      zero, 4(a0)
+    sw      zero, 8(a0)
+    sw      zero, 12(a0)
+    addu    a0, a0, 0x20
+    sw      zero, -16(a0)
+    sw      zero, -12(a0)
+    sw      zero, -8(a0)
+    sw      zero, -4(a0)
+    bne     a0, a3, 1b
+
+wordzero:
+    /* align backwards to 0x4 */
+    and     a3, a1, ~3
+    /* If the result is zero, the amount to zero is less than 0x4 bytes */
+    subu    a1, a1, a3
+    beqz    a3, bytezero
+    /* zero one word at a time */
+    addu    a3, a3, a0
+1:
+    addu    a0, a0, 4
+    sw      zero, -4(a0)
+    bne     a0, a3, 1b
+bytezero:
+    /* test if nothing left to zero */
+    blez    a1, zerodone
+    /* zero one byte at a time */
+    addu    a1, a1, a0
+1:
+    addu    a0, a0, 1
+    sb      zero, -1(a0)
+    bne     a0, a1, 1b
+zerodone:
+    jr      ra
+END(bzero)