From e52725d564fbbb79f35bdb3b9c128ee6645ea0d8 Mon Sep 17 00:00:00 2001
From: Wesley Moore <wes@wezm.net>
Date: Tue, 11 Feb 2025 22:08:32 +1000
Subject: [PATCH] Add tests for add64
Currently the test harness isn't looping, so the test is failing.
---
Makefile | 7 +++-
calc.s | 20 +---------
hex.s | 1 +
math.s | 26 +++++++++++++
tests/math_add64.s | 91 ++++++++++++++++++++++++++++++++++++++++++++++
tests/test_math.sh | 7 ++++
6 files changed, 131 insertions(+), 21 deletions(-)
create mode 100644 math.s
create mode 100644 tests/math_add64.s
create mode 100644 tests/test_math.sh
diff --git a/Makefile b/Makefile
index 0e7d818..a41a7dc 100644
--- a/Makefile
+++ b/Makefile
@@ -14,10 +14,13 @@ check: tests
hello.elf: hello.o
$(LD) -m elf32lriscv $^ -o $@
-calc.elf: mem.o hex.o debug.o calc.o
+calc.elf: mem.o hex.o debug.o math.o calc.o
$(LD) -m elf32lriscv -T link.ld $^ -o $@
-tests: tests/btohex.elf tests/tohex.elf
+tests: tests/btohex.elf tests/tohex.elf tests/math_add64.elf
+
+tests/math_add64.elf: hex.o math.o tests/math_add64.o
+ $(LD) -m elf32lriscv -T link.ld $^ -o $@
tests/btohex.elf: mem.o hex.o debug.o tests/btohex.o
$(LD) -m elf32lriscv -T link.ld $^ -o $@
diff --git a/calc.s b/calc.s
index cff8a62..f3b8bd0 100644
--- a/calc.s
+++ b/calc.s
@@ -5,6 +5,7 @@
.global _start
.extern regdump
+.extern add64
/* newlib system calls */
.set SYSEXIT, 93
@@ -28,22 +29,3 @@ _start:
li t0, SYSEXIT # "exit" syscall
add a0, x0, 0 # Use 0 return code
ecall # invoke syscall to terminate the program
-
-# 64-bit integer addition
-# arguments:
-# a0: x lower 32 bits
-# a1: x upper 32 bits
-# a2: y lower 32 bits
-# a3: y upper 32 bits
-# return:
-# a0: x+y lower 32 bits
-# a1: x+y upper 32 bits
-#
-add64:
- add a0, a0, a2 # add lower 32 bits
- add t0, a1, a3 # add upper 32 bits
- sltu t1, a0, a2 # if lower 32-bit sum < a2 then set t1=1 (carry bit)
- add a1, t0, t1 # upper 32 bits of answer (upper sum + carry bit)
- ret
-
-
diff --git a/hex.s b/hex.s
index afdc82c..3bf60a8 100644
--- a/hex.s
+++ b/hex.s
@@ -2,6 +2,7 @@
.global tohex
.section .rodata
+
hexchars:
.ascii "0123456789ABCDEF"
diff --git a/math.s b/math.s
new file mode 100644
index 0000000..2389918
--- /dev/null
+++ b/math.s
@@ -0,0 +1,26 @@
+.globl add64
+
+.text
+
+# > When primitive arguments twice the size of a pointer-word are passed on the
+# > stack, they are naturally aligned. When they are passed in the integer
+# > registers, they reside in an aligned even-odd register pair, with the even
+# > register holding the least-significant bits.
+
+# 64-bit integer addition
+# arguments:
+# a0: x lower 32 bits
+# a1: x upper 32 bits
+# a2: y lower 32 bits
+# a3: y upper 32 bits
+# return:
+# a0: x+y lower 32 bits
+# a1: x+y upper 32 bits
+#
+add64:
+ add a0, a0, a2 # add lower 32 bits
+ add t0, a1, a3 # add upper 32 bits
+ sltu t1, a0, a2 # if lower 32-bit sum < a2 then set t1=1 (carry bit)
+ add a1, t0, t1 # upper 32 bits of answer (upper sum + carry bit)
+ ret
+
diff --git a/tests/math_add64.s b/tests/math_add64.s
new file mode 100644
index 0000000..cc4589c
--- /dev/null
+++ b/tests/math_add64.s
@@ -0,0 +1,91 @@
+# Test for add64
+
+.org 0
+# Provide program starting address to linker
+.global _start
+
+.extern add64
+.extern tohex
+
+/* newlib system calls */
+.set SYSEXIT, 93
+.set SYSWRITE, 64
+
+.section .rodata
+
+inputs:
+ .word 0x40000000 # 0.25
+ .word 1 # 1
+ .word 0x40000000 # 0.25
+ .word 2 # 2
+
+ .word 0x40000000 # 0.25
+ .word 1 # 1
+ .word 0x80000000 # 0.5
+ .word 2 # 2
+
+ .set inputs_end, .-inputs
+
+.section .bss
+
+buf: .skip 9
+
+.text
+
+_start:
+ li a0, '\n
+ la a1, buf
+ sb a0, 8(a1) # append newline to buf
+
+ la s0, inputs # init loop variables
+ la s1, inputs_end
+loop:
+ lw a0, 0(s0) # a0: x lower 32 bits
+ lw a1, 4(s0) # a1: x upper 32 bits
+ lw a2, 8(s0) # a2: y lower 32 bits
+ lw a3, 12(s0) # a3: y upper 32 bits
+ jal add64
+
+ # TODO: Format as an actual decimal
+ # print the result, hi = a1, lo = a0, a1.a0
+ # a0 is value, a1 is buf addr
+ addi sp, sp, -4
+ sw a0, 0(sp) # stash a0 for later
+ mv a0, a1 # copy a1 to a0
+ la a1, buf
+ jal tohex
+
+ # print hi word
+ li t0, SYSWRITE # "write" syscall
+ li a0, 1 # 1 = standard output (stdout)
+ la a1, buf # load address of output string
+ li a2, 8 # length of output string
+ ecall # invoke syscall to print the string
+
+ # print .
+ li t0, SYSWRITE # "write" syscall
+ li a0, 1 # 1 = standard output (stdout)
+ la a1, buf # load address of output string
+ li a2, '.
+ sb a2, 0(a1)
+ li a2, 1 # length of output string
+ ecall # invoke syscall to print the string
+
+ # print lo word
+ lw a0, 0(sp) # restore lo word
+ addi sp, sp, 4
+ la a1, buf
+ jal tohex
+
+ li t0, SYSWRITE # "write" syscall
+ li a0, 1 # 1 = standard output (stdout)
+ la a1, buf # load address of output string
+ li a2, 9 # length of output string
+ ecall # invoke syscall to print the string
+
+ addi s0, s0, 16 # increment input pointer to next pair of 64-bit inputs
+ bltu s0, s1, loop # if the input address is less than inputs_end, loop
+
+ li t0, SYSEXIT # "exit" syscall
+ la a0, 0 # Use 0 return code
+ ecall # invoke syscall to terminate the program
diff --git a/tests/test_math.sh b/tests/test_math.sh
new file mode 100644
index 0000000..83307d3
--- /dev/null
+++ b/tests/test_math.sh
@@ -0,0 +1,7 @@
+#!/bin/sh
+
+test_add64() {
+ result=$("${QEMU}" -B 0x80000000 -s 2k tests/math_add64.elf)
+
+ test $? -eq 0 && test "${result}" = "00000003.80000000\n00000003.C0000000" # 3.5, 3.75
+}