From ea03f8e35d418d810036fe23c43e6060f74f2541 Mon Sep 17 00:00:00 2001 From: Ali Saidi Date: Sun, 6 Jun 2004 19:33:50 -0400 Subject: Rather than using a loop to calculate the interrupt vector, use the ctlz instruction. --- system/alpha/palcode/platform_m5.s | 31 +++++++------------------------ 1 file changed, 7 insertions(+), 24 deletions(-) (limited to 'system') diff --git a/system/alpha/palcode/platform_m5.s b/system/alpha/palcode/platform_m5.s index 7e068b100..9012fd79e 100644 --- a/system/alpha/palcode/platform_m5.s +++ b/system/alpha/palcode/platform_m5.s @@ -839,39 +839,22 @@ sys_int_21: bis r8,r9,r8 ldqp r9,0x0020(r8) // read PIC1 ISR for interrupting dev -#if 0 // we have a 21164 so this won't work because of the ctlz, if we ever change that... normal_int: - ctlz r9,r10 // count the number of leading zeros + //ctlz r9,r10 // count the number of leading zeros + // EV5 doesn't have ctlz, but we do, so lets use it + .byte 0x4a + .byte 0x06 + .byte 0xe9 + .byte 0x73 lda r11,63(r31) subq r11,r10,r17 // subtract from lda r9,0x10(r31) mulq r17,r9,r17 // compute 0x900 + (0x10 * Highest DIRn-bit) - lda r9,0x900(r31) - addq r17,r9,r17 - - br r31, pal_post_interrupt -#endif - -normal_int: - or r31,63,r17 // load 63 into the counter - or r31,1,r11 - sll r11,63,r11 // load a 1 into the msb - -find_msb: - and r9,r11,r10 - bne r10, found_msb - srl r11,1,r11 - subl r17,1,r17 - br r31, find_msb - -found_msb: - lda r9,0x10(r31) - mulq r17,r9,r17 // compute offset + (0x10 * Highest DIRn-bit) addq r17,r13,r17 br r31, pal_post_interrupt - + ALIGN_BRANCH pal_post_dev_interrupt: or r13, r31, r17 // move vector to a1 -- cgit v1.2.3